Neutralizing anti-influenza b antibodies and uses thereof

ABSTRACT

The invention relates to antibodies and antigen binding fragments thereof that are capable of binding to influenza B virus hemagglutinin (HA) and neutralizing influenza B virus in two phylogenetically distinct lineages. In one embodiment, the antibody or antigen binding fragment is capable of binding to influenza B virus hemagglutinin and neutralizing influenza B virus in Yamagata and Victoria lineages.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/325,603, filed Jan. 11, 2017, which is a U.S. National Stage ofInternational Application No. PCT/US2105/040385, filed on Jul. 14, 2015,said International Application No. PCT/US2015/040385 claims benefitunder 35 U.S.C. § 119(e) of the U.S. Provisional Application No.62/024,804, filed Jul. 15, 2014. Each of the above listed applicationsis incorporated by reference herein in its entirety for all purposes.

REFERENCE TO THE SEQUENCE LISTING

This application incorporates by reference a Sequence Listing submittedwith this application as text file entitled Seq_List_0098-0031 US2created on Nov. 16, 2016 and having a size of 77.31 kilobytes.

FIELD OF THE INVENTION

The invention relates to antibodies that have broad neutralizingactivity against influenza B virus and to uses of such antibodies.

BACKGROUND TO THE INVENTION

Influenza viruses cause annual influenza epidemics and occasionalpandemics, which pose a significant threat to public health worldwide.Seasonal influenza infection is associated with 200,000-500,000 deathseach year, particularly in young children, immunocompromised patientsand the elderly. Mortality rates typically increase further duringseasons with pandemic influenza outbreaks. There remains a significantunmet medical need for potent anti-viral therapeutics for preventing andtreating influenza infections, particularly in under-served populations.

There are three types of influenza viruses: types A, B and C. Themajority of influenza disease is caused by influenza A and B viruses(Thompson et al. (2004) JAMA. 292:1333-1340; and Zhou et al. (2012) ClinInfect. Dis. 54:1427-1436). The overall structure of influenza virusesA, B and C is similar, and includes a viral envelope which surrounds acentral core. The viral envelope includes two surface glycoproteins,Hemagglutinin (HA) and neuraminidase (NA); HA mediates binding of thevirus to target cells and entry into target cells, whereas NA isinvolved in the release of progeny virus from infected cells.

The HA protein is trimeric in structure and includes three identicalcopies of a single polypeptide precursor, HAO, which, upon proteolyticmaturation, is cleaved into a pH-dependent, metastable intermediatecontaining a globular head (HA1) and stalk region (HA2) (Wilson et al.(1981) Nature. 289:366-373). The membrane distal globular headconstitutes the majority of the HA1 structure and contains the sialicacid binding pocket for viral entry and major antigenic domains.

Influenza A viruses can be classified into subtypes based on geneticvariations in hemagglutinin (HA) and neuraminidase (NA) genes.Currently, in seasonal epidemics, influenza A H1 and H3 HA subtypes areprimarily associated with human disease, whereas viruses encoding H5,H7, H9 and H10 are associated with sporadic human outbreaks due todirect transmission from animals.

In contrast to influenza A viruses, influenza B viruses are not dividedinto subtypes based on the two surface glycoproteins and until the 1970swere classified as one homogenous group. Through the 1970s, theinfluenza B viruses started to diverge into two antigenicallydistinguishable lineages which were named the Victoria and Yamagatalineages after their first representatives, B/Victoria/2/87 andBNamagata/16/88, respectively. (Biere et al. (2010) J Clin Microbiol.48(4):1425-7; doi: 10.1128/JCM.02116-09. Epub 2010 Jan. 27). Influenza Bviruses are restricted to human infection, and both lineages contributeto annual epidemics. Although the morbidity caused by influenza Bviruses is lower than that associated with influenza A H3N2, it ishigher than that associated with influenza A H1N1 (Zhou et al. (2012)Clin Infect. Dis. 54:1427-1436).

Neutralizing antibodies elicited by influenza virus infection arenormally targeted to the variable HA1 globular head to prevent viralreceptor binding and are usually strain-specific. Broadly cross-reactiveantibodies that neutralize one or more subtype or lineage are rare.Recently, a few human antibodies have been discovered that canneutralize multiple subtypes of influenza B viruses of both lineages(Dreyfus et al. (2012) Science. 337(6100):1343-8; and Yasugi et al.(2013) PLoS Path. 9(2):e1003150). Although these antibodies recognizemany influenza B viruses, they have a limited breadth of coverage andpotency, and do not neutralize any influenza A virus strains. To date,there are no available antibodies that broadly neutralize or inhibit allinfluenza B virus infections or attenuate diseases caused by influenza Bvirus. Therefore, there is a need to identify new antibodies thatprotect against multiple of influenza viruses.

SUMMARY OF THE INVENTION

The invention described herein provides an isolated antibody or anantigen binding fragment thereof that is capable of binding to influenzaB virus hemagglutinin (HA) and neutralizing influenza B virus in twophylogenetically distinct lineages. In one embodiment, the antibody orantigen binding fragment thereof is capable of binding to influenza Bvirus hemagglutinin and neutralizing influenza B virus in both Yamagataand Victoria lineages. Yamagata lineages include, but are not limitedto: B/AA/94 (ca B/Ann Arbor/2/94 (yamagata)); BNSI/98 (caBNamanashi/166/98 (yamagata)); B/JHB/99 (ca B/Johannesburg/5/99(yamagata)); B/SC/99 (B/Sichuan/379/99 (yamagata)); B/FL/06(B/Florida/4/2006 (yamagata)). Victoria lineages include, but are notlimited to: B/BJ/97 (ca B/Beijing/243/97 (victoria)), B/HK/01 (B/HongKong/330/2001 (victoria)); B/MY/04 (B/Malaysia/2506/2004 (victoria));B/BNE/08 (ca B/Brisbane/60/2008 (victoria)).

In another embodiment, the invention provides an isolated antibody or anantigen binding fragment thereof that is capable of binding to influenzaB virus hemagglutinin and neutralizing influenza B virus in apre-divergent strain. As used herein, the term “pre-divergent” refers toinfluenza B strains that were identified prior to the divergence ofinfluenza B into Yamagata and Victoria lineages. Pre-divergent influenzaB strains include, but are not limited to: B/Lee/40 (B/Lee/40); B/AA/66(ca B/Ann Arbor/1/66); and B/HK/72 (B/Hong Kong/5/72).

In one embodiment, the antibody or antigen binding fragment bindsinfluenza B virus with an E0₅₀ in the range of from about 1 μg/ml toabout 50 μg/ml of antibody. In another embodiment, the antibody orantigen binding fragment has a neutralizing potency expressed as 50%inhibitory concentration (IC₅₀ μg/ml) in the range of from about 0.001μg/ml to about 5 μg/ml of antibody for neutralization of influenza Bvirus in a microneutralization assay as described in Example 3. Othermicroneutralization assays are also described in Example 1.

In one embodiment, the antibody is capable of binding to influenza Avirus hemagglutinin. Influenza A virus hemagglutinin includes subtype 1and subtype 2 hemagglutinin. Influenza A virus group 1 subtypes include:H1, H2, H5, H6, H8, H9, H11, H12, H13, H16 and variants thereof.Influenza A virus group 2 subtype include: H3, H4, H7, H10, H14 and H15and variants thereof. In one embodiment, the antibody is capable ofbinding to one or more influenza A virus group 1 subtypes. In anotherembodiment, the antibody is capable of binding to one or more influenzaA virus group 2 subtypes. In one embodiment, the antibody is capable ofbinding to influenza A virus group 1 subtype H9. In one embodiment, theinvention provides an isolated antibody or an antigen binding fragmentthereof that is capable of binding to influenza B virus hemagglutinin(HA) and influenza A virus hemagglutinin (HA) and neutralizing at leastone Yamagata lineage influenza B virus; at least one Victoria lineageinfluenza B virus; at least one influenza A virus subtype, orcombinations thereof. In one embodiment, the invention provides anisolated antibody or an antigen binding fragment thereof that is capableof binding to influenza B virus hemagglutinin (HA) and one or moreinfluenza A virus subtype 1 hemagglutinin (HA) and neutralizing at leastone Yamagata lineage influenza B virus or at least one Victoria lineageinfluenza B virus and at least one influenza A virus subtype 1. In oneembodiment, the invention provides an isolated antibody or an antigenbinding fragment thereof that is capable of binding to influenza B virushemagglutinin (HA) and influenza A virus subtype H9 hemagglutinin (HA)and neutralizing at least one Yamagata lineage influenza B virus; atleast one Victoria lineage influenza B virus; influenza A virus subtypeH9, or combinations thereof.

In one embodiment, the antibody or antigen binding fragment bindsinfluenza A HA at an EC₅₀ in the range of from about 1 μg/ml to about 50μg/ml of antibody. In another embodiment, the antibody or antigenbinding fragment has an IC₅₀ in the range of from about 0.01 μg/ml toabout 5 μg/ml of antibody for neutralization of influenza A virus in amicroneutralization assay.

In one embodiment, an antibody or fragment thereof of the inventionbinds to the globular head region of HA and neutralizes infection ofinfluenza B virus in two phylogenetically distinct lineages. In anotherembodiment, the antibody or antigen binding fragment thereof binds tothe globular head region of HA and neutralizes infection of influenza Bvirus from both Yamagata and Victoria lineages. Antibodies of theinvention, which are anti-Influenza B HA globular head bindingantibodies, demonstrate a broader breath of coverage or betterneutralizing activity against influenza B viruses compared to knownanti-influenza B antibodies.

In one embodiment, the antibody or antigen binding fragment thereofincludes a set of six CDRs: HCDR-1, HCDR-2, HCDR-3, LCDR-1, LCDR-2,LCDR-3, in which the set of six CDRs is selected from:

-   -   (a) HCDR-1 of SEQ ID NO.: 3, HCDR-2 of SEQ ID NO.: 4, HCDR-3 of        SEQ ID NO.: 5, LCDR-1 of SEQ ID NO.: 8, LCDR-2 of SEQ ID NO.: 9        and LCDR-3 of SEQ ID NO.: 10;    -   (b) HCDR-1 of SEQ ID NO.: 13, HCDR-2 of SEQ ID NO.: 14, HCDR-3        of SEQ ID NO.: 15, LCDR-1 of SEQ ID NO.: 18, LCDR-2 of SEQ ID        NO.: 19, LCDR-3 of SEQ ID NO.: 20;    -   (c) HCDR-1 of SEQ ID NO.: 23, HCDR-2 of SEQ ID NO.: 24, HCDR-3        of SEQ ID NO.: 25, LCDR-1 of SEQ ID NO.: 28, LCDR-2 of SEQ ID        NO.: 29 and LCDR-3 of SEQ ID NO.: 30;    -   (d) HCDR-1 of SEQ ID NO.: 33, HCDR-2 of SEQ ID NO.: 34, HCDR-3        of SEQ ID NO.: 35, LCDR-1 of SEQ ID NO.: 38, LCDR-2 of SEQ ID        NO.: 39 and LCDR-3 of SEQ ID NO.: 40;    -   (e) HCDR-1 of SEQ ID NO.: 43, HCDR-2 of SEQ ID NO.: 44, HCDR-3        of SEQ ID NO.: 45, LCDR-1 of SEQ ID NO.: 48, LCDR-2 of SEQ ID        NO.: 49 and LCDR-3 of SEQ ID NO.: 50;    -   (f) HCDR-1 of SEQ ID NO.: 53, HCDR-2 of SEQ ID NO.: 54, HCDR-3        of SEQ ID NO.: 55, LCDR-1 of SEQ ID NO.: 58, LCDR-2 of SEQ ID        NO.: 59 and LCDR-3 of SEQ ID NO.: 60;    -   (g) HCDR-1 of SEQ ID NO.: 63, HCDR-2 of SEQ ID NO.: 64, HCDR-3        of SEQ ID NO.: 65, LCDR-1 of SEQ ID NO.: 68, LCDR-2 of SEQ ID        NO.: 69 and LCDR-3 of SEQ ID NO.: 70;    -   (h) HCDR-1 of SEQ ID NO.: 75, HCDR-2 of SEQ ID NO.: 76, HCDR-3        of SEQ ID NO.: 77, LCDR-1 of SEQ ID NO.: 83, LCDR-2 of SEQ ID        NO.: 84 and LCDR-3 of SEQ ID NO.: 85;    -   (i) HCDR-1 of SEQ ID NO.: 91, HCDR-2 of SEQ ID NO.: 92, HCDR-3        of SEQ ID NO.: 93, LCDR-1 of SEQ ID NO.: 99, LCDR-2 of SEQ ID        NO.: 100 and LCDR-3 of SEQ ID NO.: 101;    -   (j) HCDR-1 of SEQ ID NO.: 107, HCDR-2 of SEQ ID NO.: 108, HCDR-3        of SEQ ID NO.: 109, LCDR-1 of SEQ ID NO.: 115, LCDR-2 of SEQ ID        NO.: 116 and LCDR-3 of SEQ ID NO.: 117;    -   (k) HCDR-1 of SEQ ID NO.: 121, HCDR-2 of SEQ ID NO.: 122, HCDR-3        of SEQ ID NO.: 123, LCDR-1 of SEQ ID NO.: 124, LCDR-2 of SEQ ID        NO.: 125 and LCDR-3 of SEQ ID NO.: 126;    -   (l) HCDR-1 of SEQ ID NO.: 127, HCDR-2 of SEQ ID NO.: 128, HCDR-3        of SEQ ID NO.: 129, LCDR-1 of SEQ ID NO.: 130, LCDR-2 of SEQ ID        NO.: 131 and LCDR-3 of SEQ ID NO.: 132;    -   (m) HCDR-1 of SEQ ID NO.: 133, HCDR-2 of SEQ ID NO.: 134, HCDR-3        of SEQ ID NO.: 135, LCDR-1 of SEQ ID NO.: 136, LCDR-2 of SEQ ID        NO.: 137 and LCDR-3 of SEQ ID NO.: 138;    -   (n) HCDR-1 of SEQ ID NO.: 139, HCDR-2 of SEQ ID NO.: 140, HCDR-3        of SEQ ID NO.: 141, LCDR-1 of SEQ ID NO.: 142, LCDR-2 of SEQ ID        NO.: 143 and LCDR-3 of SEQ ID NO.: 144;    -   (o) HCDR-1 of SEQ ID NO.: 145, HCDR-2 of SEQ ID NO.: 146, HCDR-3        of SEQ ID NO.: 147, LCDR-1 of SEQ ID NO.: 148, LCDR-2 of SEQ ID        NO.: 149 and LCDR-3 of SEQ ID NO.: 150;    -   (p) HCDR-1 of SEQ ID NO.: 78, HCDR-2 of SEQ ID NO.: 79, HCDR-3        of SEQ ID NO.: 80, LCDR-1 of SEQ ID NO.: 86, LCDR-2 of SEQ ID        NO.: 87 and LCDR-3 of SEQ ID NO.: 88;    -   (q) HCDR-1 of SEQ ID NO.: 94, HCDR-2 of SEQ ID NO.: 95, HCDR-3        of SEQ ID NO.: 96, LCDR-1 of SEQ ID NO.: 102, LCDR-2 of SEQ ID        NO.: 103 and LCDR-3 of SEQ ID NO.: 104;    -   (r) HCDR-1 of SEQ ID NO.: 110, HCDR-2 of SEQ ID NO.: 111, HCDR-3        of SEQ ID NO.: 112, LCDR-1 of SEQ ID NO.: 118, LCDR-2 of SEQ ID        NO.: 119 and LCDR-3 of SEQ ID NO.: 120; and    -   (s) a set of six CDRS according to any one of (a) to (r)        including one or more amino acid substitutions, deletions or        insertions.

In another embodiment, antibody or antigen binding fragment thereof hasa VH having at least 75%, 80%, 85%, 90%, 95% or 100% identity and/or aVL having at least 75%, 80%, 85%, 90%, 95% or 100% identity to a VHand/or VL, respectively, selected from:

-   -   (a) VH of SEQ ID NO.: 2 and VL of SEQ ID NO.: 7,    -   (b) VH of SEQ ID NO.: 12 and VL of SEQ ID NO.: 17,    -   (c) VH of SEQ ID NO.: 22 and VL of SEQ ID NO.: 27,    -   (d) VH of SEQ ID NO.: 32 and VL of SEQ ID NO.: 37,    -   (e) VH of SEQ ID NO.: 42 and VL of SEQ ID NO.: 47,    -   (f) VH of SEQ ID NO.: 52 and VL of SEQ ID NO.: 57,    -   (g) VH of SEQ ID NO.: 62 and VL of SEQ ID NO.: 67,    -   (h) VH of SEQ ID NO.: 74 and VL of SEQ ID NO.: 82,    -   (i) VH of SEQ ID NO.: 90 and VL of SEQ ID NO.: 98, and    -   (j) VH of SEQ ID NO.: 106 and VL of SEQ ID NO.: 114.

In a more particular embodiment, the antibody or antigen bindingfragment thereof includes a VH and a VL selected from:

-   -   (a) VH of SEQ ID NO.: 2 and VL of SEQ ID NO.: 7,    -   (b) VH of SEQ ID NO.: 12 and VL of SEQ ID NO.: 17,    -   (c) VH of SEQ ID NO.: 22 and VL of SEQ ID NO.: 27,    -   (d) VH of SEQ ID NO.: 32 and VL of SEQ ID NO.: 37,    -   (e) VH of SEQ ID NO.: 42 and VL of SEQ ID NO.: 47,    -   (f) VH of SEQ ID NO.: 52 and VL of SEQ ID NO.: 57,    -   (g) VH of SEQ ID NO.: 62 and VL of SEQ ID NO.: 67,    -   (h) VH of SEQ ID NO.: 74 and VL of SEQ ID NO.: 82,    -   (i) VH of SEQ ID NO.: 90 and VL of SEQ ID NO.: 98, and    -   (j) VH of SEQ ID NO.: 106 and VL of SEQ ID NO.: 114.

In one embodiment, the invention provides an antibody or antigen bindingfragment thereof that is capable of binding to influenza B virushemagglutinin (HA) and neutralizing influenza B virus in twophylogenetically distinct lineages, wherein the antibody has a VH aminoacid sequence of SEQ ID NO:71, wherein Xaa₁ of SEQ ID NO:71 is Val orGlu; Xaa₂ SEQ ID NO:71 is Leu or Phe; Xaa₃ SEQ ID NO:71 is Ser or Thr;Xaa₄ SEQ ID NO:71 is Leu or Ser; Xaa₅ SEQ ID NO:71 is Ser or Thr; Xaa₆SEQ ID NO:71 is Met or Thr; Xaa₇ SEQ ID NO:71 is Phe or Tyr; Xaa₈ SEQ IDNO:71 is His or Gln; Xaa₉ SEQ ID NO:71 is Ser or Asn; Xaa₁₀ SEQ ID NO:71is Arg or Lys; and Xaa₁₁ SEQ ID NO:71 is Ala or Thr; and an VL aminoacid sequence of SEQ ID NO:72, wherein Xaa₁ of SEQ ID NO:72 is Phe orTyr. In one embodiment, Xaa₉ of SEQ ID NO:71 is Ser. In anotherembodiment, Xaa₄ of SEQ ID NO:71 is Leu. In yet another embodiment, Xaa₁of SEQ ID NO:71 is Glu; Xaa₅ of SEQ ID NO:71 is Thr; Xaa₆ of SEQ IDNO:71 is Thr; Xaa₇ of SEQ ID NO:71 is Tyr; Xaa₈ of SEQ ID NO:71 is Gln;Xaa₁₀ of SEQ ID NO:71 is Lys; Xaa₁₁ of SEQ ID NO:71 is Thr, orcombinations thereof. In another embodiment, Xaa₁ of SEQ ID NO:71 isGlu; Xaa₅ of SEQ ID NO:71 is Thr; Xaa₆ of SEQ ID NO:71 is Thr; Xaa₇ ofSEQ ID NO:71 is Tyr; Xaa₈ of SEQ ID NO:71 is Gln; Xaa₉ of SEQ ID NO:71is Ser; Xaa₁₀ of SEQ ID NO:71 is Lys; and Xaa₁₁ of SEQ ID NO:71 is Thr.

In one embodiment, the antibody or antigen binding fragment thereof isselected from: an immunoglobulin molecule, a monoclonal antibody, achimeric antibody, a CDR-grafted antibody, a humanized antibody, a Fab,a Fab′, a F(ab′)2, a Fv, a disulfide linked Fv, a scFv, a single domainantibody, a diabody, a multispecific antibody, a dual-specific antibody,and a bispecific antibody. In one embodiment, the antibody or antigenbinding fragment thereof includes an Fc region. In one embodiment, theantibody or antigen binding fragment thereof is an IgG1, IgG2 or IgG4 orfragment thereof.

In one embodiment, the invention provides an antibody to influenza Bvirus or an antigen binding fragment thereof that is capable of bindingto influenza B virus and neutralizing at least one Yamagata lineage andat least one Victoria lineage of influenza B virus, wherein the antibodyor antigen binding fragment thereof binds an epitope that is conservedamong at least one Yamagata lineage, and at least one Victoria lineageof influenza B virus. In one embodiment, one or more contact residues ofthe epitope are located in a head region of influenza B HA. In oneembodiment, the epitope includes one or more amino acids selected from:128, 141, 150 and 235 of the sequence of the head region of HA ascontact residues (Wang et al. (2008) J. Virol. 82(6):3011-20).

In another embodiment, the invention provides an antibody to influenza Bvirus or an antigen binding fragment thereof that is capable of bindingto influenza B virus hemagglutinin and neutralizing influenza B virus intwo phylogenetically distinct lineages that binds to the same epitope asor competes for binding to influenza B virus hemagglutinin with anantibody of the invention. In one embodiment, the antibody or antigenbinding fragment binds to the same epitope or competes for binding toinfluenza A virus hemagglutinin with an antibody having an amino acidsequence selected from:

-   -   (a) VH of SEQ ID NO.: 2 and VL of SEQ ID NO.: 7,    -   (b) VH of SEQ ID NO.: 12 and VL of SEQ ID NO.: 17,    -   (c) VH of SEQ ID NO.: 22 and VL of SEQ ID NO.: 27,    -   (d) VH of SEQ ID NO.: 32 and VL of SEQ ID NO.: 37,    -   (e) VH of SEQ ID NO.: 42 and VL of SEQ ID NO.: 47,    -   (f) VH of SEQ ID NO.: 52 and VL of SEQ ID NO.: 57,    -   (g) VH of SEQ ID NO.: 62 and VL of SEQ ID NO.: 67,    -   (h) VH of SEQ ID NO.: 74 and VL of SEQ ID NO.: 82,    -   (i) VH of SEQ ID NO.: 90 and VL of SEQ ID NO.: 98, and    -   (j) VH of SEQ ID NO.: 106 and VL of SEQ ID NO.: 114.

The invention also provides an isolated nucleic acid encoding anantibody or antigen binding fragment thereof of the invention, as wellas a vector that includes such an isolated nucleic acid and a host cellthat includes such a nucleic acid or vector. In one embodiment, thevector is an expression vector. In another embodiment, the vector is anon-naturally occurring recombinant vector. In one embodiment, thevector is a plasmid. In one embodiment, the vector or plasmid includes anucleotide sequence encoding an antibody molecule of the invention, orantigen binding fragment thereof, a heavy or light chain of an antibodymolecule of the invention, a heavy or light chain variable domain of anantibody of the invention, or a portion thereof, or a heavy or lightchain CDR, operably linked to one or more expression control elements(e.g., promoter, enhancer, transcription terminators, polyadenylationsites, etc.), a selectable marker gene, or combinations thereof. In oneembodiment, the vector or plasmid includes at least one heterologousexpression control element, selectable marker, or combinations thereof.

In one embodiment, the invention provides a method for manufacturing anantibody or antigen binding fragment thereof by culturing a host celldescribed herein under conditions suitable for expression of theantibody or fragment thereof. In one embodiment, the method includesisolating the antibody or antigen binding fragment thereof from the hostcell culture. In one embodiment the host cell is isolated from tissuesin which the cell is naturally found. For example, a host cell can beisolated from an organism and maintained ex vivo in a cell culture.

The invention also provides a composition that includes an antibody orantigen binding fragment thereof of the invention and a pharmaceuticallyacceptable carrier. In one embodiment, the composition includes anantibody or antigen binding fragment thereof of the invention and 25 mMHis and 0.15M NaCl at pH 6.0

In one embodiment, the antibody or antigen binding fragment thereof ofthe invention is used in the prophylaxis or treatment of influenza Binfection in a subject. In another embodiment, the antibody or antigenbinding fragment thereof is used in the prophylaxis or treatment ofinfluenza A and influenza B infection in a subject. In anotherembodiment, the antibody or antigen binding fragment thereof of theinvention is used in the manufacture of a medicament for the prophylaxisor treatment of influenza B infection in a subject. In anotherembodiment, the antibody or antigen binding fragment thereof of theinvention is used in the manufacture of a medicament for the prophylaxisor treatment of influenza A and influenza B infection in a subject.

In one embodiment, the invention provides a method for prophylaxis ortreatment of influenza B infection in a subject, which includesadministering an effective amount of an antibody or antigen bindingfragment thereof of the invention to the subject. In another embodiment,the invention provides method for prophylaxis or treatment of influenzaA and influenza B infection in a subject, which includes administeringan effective amount of an antibody or antigen binding fragment thereofof the invention to the subject.

In one embodiment, the antibody or fragment thereof of the invention isused for in vitro diagnosis of influenza B infection in a subject. Inanother embodiment, the antibody or fragment thereof of the invention isused for in vitro diagnosis of influenza A infection in a subject. Inyet another embodiment, the antibody or fragment thereof of theinvention is used for in vitro diagnosis of influenza A infection andinfluenza B infection in a subject.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the antibody-dependent cellular cytotoxicity (ADCC) asmeasured by NK cell activation after incubation with B/HongKong/330/2001(Victoria lineage) and a serial dilution of anti-HA antibodies FBD-94and FBC-39, as well as variants that lack Fc-effector function (FBD-94LALA and FBC-39 LALA).

FIG. 2 shows the percentage of surviving animals that were administeredwith different concentrations of FBC-39 (A and C), FBD-94 (B and D) anda non-relevant control antibody 4 hours before infection with a lethaldose of B/Sichuan/379/99 (Yamagata) (A and B) or B/Hong Kong/330/2001(Victoria) (C and D) influenza virus.

FIG. 3 shows the percentage of surviving animals that were infected witha lethal dose of B/Sichuan/379/99 (Yamagata) (A and B) or B/HongKong/330/2001 (Victoria) (C and D) and treated on day 2 post-infectionwith different doses of FBC-39 (A and C) or FBD-94 (B and D), or anon-relevant control antibody.

FIG. 4 shows the percentage of surviving animals that were infected witha lethal dose of B/Hong Kong/330/2001 (Victoria) and treated at 1, 2, 3,or 4 days post-infection with 3 mg/kg of FBC-39 (A) or FBD-94 (B), or anon-relevant control antibody.

FIG. 5 shows the CDRs (boxed) within the VH and VL sequences ofanti-influenza B antibodies FBD-56, FBD-94, FBC-39, FBC-39 LSL, FBC-39FSL, FBC-39 LTL, FBC-39 FTL, FBC-39 FSS, FBC-39 LTS, and FBC-39 FTSusing the Kabat and IMGT numbering systems. Modified amino acids withinthe VH and VL sequences are bolded and underlined.

FIG. 6 shows the heavy chain amino acid sequence of a genericizedanti-influenza B antibody (SEQ ID NO:71), based on the heavy chain aminoacid sequence of FBC-39 (SEQ ID NO:22), wherein Xaa₁ can be Val or Glu;Xaa₂ can be Leu or Phe; Xaa₃ can be Thr or Ser; Xaa₄ can be Ser or Leu;Xaa₅ can be Thr or Ser; Xaa₆ can be Thr or Met; Xaa₇ can be Tyr or Phe;Xaa₈ can be Gln or His; Xaa₉ can be Asn or Ser; Xaa₁₀ can be Lys or Arg;and Xaa₁₁ can be Thr or Ala.

FIG. 7 shows the light chain amino acid sequence of a genericizedanti-influenza B antibody (SEQ ID NO:72), based on the light chain aminoacid sequence of FBC-39 (SEQ ID NO:27), wherein Xaa₁ can be Phe or Tyr.

FIG. 8 shows the alignment of the HA1 proteins from the viruses used inthe monoclonal antibody resistant mutant (MARM) isolation. Amino acidpositions found to be contact residues through MARM selection are boxed.

DETAILED DESCRIPTION

Introduction

The present invention provides antibodies, including human forms, aswell as antigen binding fragments, derivatives/conjugates andcompositions thereof that bind to influenza B virus hemagglutinin (HA)and neutralize influenza B virus in two phylogenetically distinctlineages as described herein. In one embodiment, the antibodies orantigen binding fragments thereof bind to influenza B virushemagglutinin (HA) and neutralize influenza B virus in both Yamagata andVictoria lineages as described herein; such anti-influenza B antibodiesand fragments thereof are referred to herein as antibodies of theinvention. In another embodiment, the antibodies or antigen bindingfragments thereof bind influenza B virus hemagglutinin (HA) andinfluenza A virus hemagglutinin (HA) and neutralize at least oneYamagata lineage influenza B virus; at least one Victoria lineageinfluenza B virus; at least one influenza A virus subtype, orcombinations thereof. Such anti-influenza B antibodies and fragmentsthereof are also referred to herein as antibodies of the invention.

As used herein, the term “neutralize” refers to the ability of anantibody, or antigen binding fragment thereof, to bind to an infectiousagent, such as influenza A and/or B virus, and reduce the biologicalactivity, for example, virulence, of the infectious agent. In oneembodiment, the antibody or antigen binding fragment thereof of theinvention immunospecifically binds at least one specified epitope orantigenic determinant of the influenza A virus; influenza B virus, orcombinations thereof. In a more particular embodiment, the antibody orantigen binding fragment thereof of the invention immunospecificallybinds at least one specified epitope or antigenic determinant ofinfluenza B virus hemagglutinin (HA). In another more particularembodiment, the antibody or binding fragment thereof of the inventionimmunospecifically binds at least one specified epitope or antigenicdeterminant of the Influenza B virus HA globular head.

An antibody can neutralize the activity of an infectious agent, such asinfluenza A and/or influenza B virus at various points during thelifecycle of the virus. For example, an antibody may interfere withviral attachment to a target cell by interfering with the interaction ofthe virus and one or more cell surface receptors. Alternately, anantibody may interfere with one or more post-attachment interactions ofthe virus with its receptors, for example, by interfering with viralinternalization by receptor-mediated endocytosis.

As used herein, the terms “antibody” and “antibodies”, also known asimmunoglobulins, encompass monoclonal antibodies (including full-lengthmonoclonal antibodies), human antibodies, humanized antibodies, camelidantibodies, chimeric antibodies, single-chain Fvs (scFv), single-chainantibodies, single domain antibodies, domain antibodies, Fab fragments,F(ab′)2 fragments, antibody fragments that exhibit the desiredbiological activity (e.g. the antigen binding portion), disulfide-linkedFvs (dsFv), and anti-idiotypic (anti-Id) antibodies (including, e.g.,anti-Id antibodies to antibodies of the invention), intrabodies, andepitope-binding fragments of any of the above. In particular, antibodiesinclude immunoglobulin molecules and immunologically active fragments ofimmunoglobulin molecules, i.e., molecules that contain at least oneantigen-binding site. Immunoglobulin molecules can be of any isotype(e.g., IgG, IgE, IgM, IgD, IgA and IgY), subisotype (e.g., IgG1, IgG2,IgG3, IgG4, IgA1 and IgA2) or allotype (e.g., Gm, e.g., G1m(f, z, a orx), G2m(n), G3m(g, b, or c), Am, Em, and Km(1, 2 or 3)).

Human antibodies are usually heterotetrameric glycoproteins of about150,000 daltons, which include two identical light (L) chains and twoidentical heavy (H) chains. Each light chain is linked to a heavy chainby one covalent disulfide bond, while the number of disulfide linkagesvaries between the heavy chains of different immunoglobulin isotypes.Each heavy and light chain also has regularly spaced intrachaindisulfide bridges. Each heavy chain has at one end a variable domain(VH) followed by a number of constant domains (CH). Each light chain hasa variable domain at one end (VL) and a constant domain (CL) at itsother end; the constant domain of the light chain is aligned with thefirst constant domain of the heavy chain, and the light chain variabledomain is aligned with the variable domain of the heavy chain. Lightchains are classified as either lambda chains or kappa chains based onthe amino acid sequence of the light chain constant region. The variabledomain of a kappa light chain may also be denoted herein as VK.

The antibodies of the invention include full length or intact antibody,antibody fragments, including antigen binding fragments, native sequenceantibody or amino acid variants, human, humanized, post-translationallymodified, chimeric or fusion antibodies, immunoconjugates, andfunctional fragments thereof. The antibodies can be modified in the Fcregion to provide desired effector functions or serum half-life. Asdiscussed in more detail in the sections below, with the appropriate Fcregions, the naked antibody bound on the cell surface can inducecytotoxicity, e.g., via antibody-dependent cellular cytotoxicity (ADCC)or by recruiting complement in complement dependent cytotoxicity (CDC),or by recruiting nonspecific cytotoxic cells that express one or moreeffector ligands that recognize bound antibody on the influenza A and/orinfluenza B virus and subsequently cause phagocytosis of the cell inantibody dependent cell-mediated phagocytosis (ADCP), or some othermechanism. Alternatively, where it is desirable to eliminate or reduceeffector function, so as to minimize side effects or therapeuticcomplications, certain other Fc regions may be used. Methods forenhancing as well as reducing or eliminating Fc-effector function aredescribed herein. Additionally, the Fc region of the antibodies of theinvention can be modified to increase the binding affinity for FcRn andthus increase serum half-life. Alternatively, the Fc region can beconjugated to PEG or albumin to increase the serum half-life, or someother conjugation that results in the desired effect.

In one embodiment, the antibodies are useful for diagnosing, preventing,treating and/or alleviating one or more symptoms of influenza B virusinfection in a mammal. In another embodiment, the antibodies are usefulfor diagnosing, preventing, treating and/or alleviating one or moresymptoms of influenza A and influenza B virus infection in an animal. Asused herein the term “animal” refers to mammals including, but notlimited to, humans, non-human primates, dogs, cats, horses, rabbits,mice, and rats; and non-mammalian species, including, but not limitedto, avian species such as chickens, turkeys, ducks, and quail.

The invention provides a composition that includes an antibody of theinvention and a carrier. For the purposes of preventing or treatinginfluenza B virus infection, compositions can be administered to thepatient in need of such treatment. In one embodiment, the compositioncan be administered to a patient for preventing or treating influenza Avirus infection; influenza B virus infection; and combinations thereof.The invention also provides formulations that include an antibody of theinvention and a carrier. In one embodiment, the formulation is atherapeutic formulation that includes a pharmaceutically acceptablecarrier.

In certain embodiments, the invention provides methods useful forpreventing or treating influenza B infection in a mammal, includingadministering a therapeutically effective amount of the antibody to themammal. In other embodiments, the invention provides methods useful forpreventing or treating influenza A infection; influenza B infection; andcombinations thereof in a mammal, including administering atherapeutically effective amount of the antibody to the mammal. Theantibody therapeutic compositions can be administered short term(acutely), chronically, or intermittently as directed by physician.

In certain embodiments, the invention also provides articles ofmanufacture that include at least an antibody of the invention, such assterile dosage forms and kits. Kits can be provided which contain theantibodies for detection and quantitation of influenza virus in vitro,e.g. in an ELISA or a Western blot. Such antibody useful for detectionmay be provided with a label such as a fluorescent or radiolabel.

Terminology

Before describing the present invention in detail, it is to beunderstood that this invention is not limited to specific compositionsor process steps, as such may vary. It must be noted that, as used inthis specification and the appended claims, the singular form “a”, “an”and “the” include plural referents unless the context clearly dictatesotherwise.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention is related. For example, the ConciseDictionary of Biomedicine and Molecular Biology, Juo, Pei-Show (2002)2nd ed. CRC Press; The Dictionary of Cell and Molecular Biology, 3rd ed.(1999) Academic Press; and the Oxford Dictionary Of Biochemistry AndMolecular Biology, Revised (2000) Oxford University Press, provide oneof skill with a general dictionary of many of the terms used in thisinvention.

Amino acids may be referred to herein by either their commonly knownthree letter symbols or by the one-letter symbols recommended by theIUPAC-IUB Biochemical Nomenclature Commission. Nucleotides, likewise,may be referred to by their commonly accepted single-letter codes.

Anti-Influenza B Virus Antibodies

In certain embodiments, the antibodies are isolated and/or purifiedand/or pyrogen free antibodies. The term “purified” as used herein,refers to other molecules, e.g., polypeptide, nucleic acid molecule thathave been identified and separated and/or recovered from a component ofits natural environment. Thus, in one embodiment the antibodies of theinvention are purified antibodies wherein they have been separated fromone or more components of their natural environment. The term “isolatedantibody” as used herein refers to an antibody which is substantiallyfree of other antibody molecules having different antigenicspecificities (e.g., an isolated antibody that specifically binds toinfluenza B virus that is substantially free of antibodies thatspecifically bind antigens other than those of the influenza B virus HAantibody). Thus, in one embodiment, the antibodies of the invention areisolated antibodies that have been separated from antibodies with adifferent specificity. Typically, an isolated antibody is a monoclonalantibody.

Moreover, an isolated antibody of the invention may be substantiallyfree of one or more other cellular materials and/or chemicals and isherein referred to an isolated and purified antibody. In one embodimentof the invention, a combination of “isolated” monoclonal antibodiesrelates to antibodies having different specificities and being combinedin a well-defined composition. Methods of production andpurification/isolation of antibodies are described below in more detail.

The isolated antibodies of the present invention include antibody aminoacid sequences disclosed herein encoded by any suitable polynucleotide,or any isolated or formulated antibody.

The antibodies of the invention immunospecifically bind at least onespecified epitope specific to the influenza B virus HA protein. The term“epitope” as used herein refers to a protein determinant capable ofbinding to an antibody. Epitopes usually include chemically activesurface groupings of molecules such as amino acids or sugar side chainsand usually have specific three dimensional structural characteristics,as well as specific charge characteristics. Conformational andnon-conformational epitopes are distinguished in that the binding to theformer but not the latter is lost in the presence of denaturingsolvents.

In one embodiment, the antibody or antigen binding fragment thereofbinds to an epitope present on at least two phylogenetically distinctinfluenza B lineages. In a more particular embodiment, the antibody orantigen binding fragment thereof binds to an epitope present in at leastone influenza B Yamagata strain and at least one influenza B Victoriastrain. In one embodiment, the antibody or antigen binding fragmentthereof binds to an epitope that is present in influenza B virus of bothYamagata lineage and Victoria lineage. In one embodiment, the antibodyor antigen binding fragment thereof binds to an epitope that isconserved among influenza B of both Yamagata lineage and Victorialineage.

In one embodiment, the antibody or antigen binding fragment thereofbinds to at least one influenza B Yamagata strain and at least oneinfluenza B Victoria strain with a half maximal effective concentration(EC₅₀) of between about 1 ng/ml and about 500 ng/ml, or between about 1ng/ml and about 250 ng/ml, or between about 1 ng/ml and about 50 ng/ml,or less than about 500 ng/ml, 250 ng/ml, 100 ng/ml, 50 ng/ml, 40 ng/ml,30 ng/ml, 20 ng/ml, or 15 μg/ml. In another embodiment, the antibody orantigen binding fragment thereof binds to influenza B virus of Yamagataand Victoria lineage with an EC₅₀ of between about 1 ng/ml and about 500ng/ml, or between about 1 ng/ml and about 250 ng/ml, or between about 1ng/ml and about 50 ng/ml, or less than about 500 ng/ml, 250 ng/ml, 100ng/ml, 50 ng/ml, 40 ng/ml, 30 ng/ml, 20 ng/ml, or 15 μg/ml. In oneembodiment, the antibody or antigen binding fragment thereof binds to anepitope present in influenza B virus of both Yamagata lineage andVictoria lineage with an EC₅₀ of between about 1 ng/ml and about 500ng/ml, or between about 1 ng/ml and about 250 ng/ml, or between about 1ng/ml and about 50 ng/ml, or less than about 500 ng/ml, 250 ng/ml, 100ng/ml, 50 ng/ml, 40 ng/ml, 30 ng/ml, 20 ng/ml, or 15 μg/ml.

In one embodiment, the antibody or antigen binding fragment thereofbinds to: an epitope present on influenza B Yamagata lineage at an EC₅₀of between about 1 ng/ml and about 100 ng/ml, 1 ng/ml and about 50ng/ml, or between about 1 ng/ml and about 25 ng/ml, or less than about50 ng/ml or 25 ng/ml; and an epitope present on influenza B Victorialineage at an EC₅₀ of between about 1 ng/ml and about 500 ng/ml, orbetween about 1 ng/ml and about 250 ng/ml, or between about 1 ng/ml andabout 50 ng/ml, or less than about 500 ng/ml, 250 ng/ml, 100 ng/ml or 50ng/ml.

In another embodiment, the antibody or antigen binding fragment thereofbinds to: an epitope present on influenza B Yamagata lineage at an EC₅₀of between about 1 ng/ml and about 100 ng/ml, 1 ng/ml and about 50ng/ml, or between about 1 ng/ml and about 25 ng/ml, or less than about50 ng/ml or 25 ng/ml; an epitope present on influenza B Victoria lineageat an EC₅₀ of between about 1 ng/ml and about 500 ng/ml, or betweenabout 1 ng/ml and about 250 ng/ml, or between about 1 ng/ml and about 50ng/ml, or less than about 500 ng/ml, 250 ng/ml or 100 ng/ml; and anepitope on influenza A HA with an EC₅₀ of between about 1 μg/ml andabout 50 μg/ml, or less than about 50 μg/ml, 25 μg/ml, 15 μg/ml or 10μg/ml. In another embodiment, the antibody or antigen binding fragmentthereof binds to: an epitope present on influenza B Yamagata lineage atan EC₅₀ of between about 1 ng/ml and about 100 ng/ml, 1 ng/ml and about50 ng/ml, or between about 1 ng/ml and about 25 ng/ml, or less thanabout 50 ng/ml or 25 ng/ml; an epitope present on influenza B Victorialineage at an EC₅₀ of between about 1 ng/ml and about 500 ng/ml, orbetween about 1 ng/ml and about 250 ng/ml, or between about 1 ng/ml andabout 50 ng/ml, or less than about 500 ng/ml, 250 ng/ml or 100 ng/ml;and an epitope on influenza A H9 HA with an EC₅₀ of between about 1μg/ml and about 50 μg/ml, or less than about 50 μg/ml, 25 μg/ml, 15μg/ml or 10 μg/ml.

In one embodiment, the antibody or antigen binding fragment thereofrecognizes an epitope that is either a linear epitope, or continuousepitope. In another embodiment, the antibody or antigen binding fragmentthereof recognizes a non-linear or conformational epitope. In oneembodiment, the epitope is located on the hemagglutinin (HA)glycoprotein of influenza B. In a more particular embodiment, theepitope is located on the head region of the HA glycoprotein ofinfluenza B. In one embodiment, the epitope includes one or more aminoacids at positions 128, 141, 150 or 235 in the head region of influenzaB HA as contact residues, which are numbered according to the H3numbering system as described in Wang et al. (2008) J. Virol.82(6):3011-20. In one embodiment, the epitope includes amino acid 128 ofthe sequence of the head region of influenza B HA as a contact residue.In another embodiment, the epitope includes amino acids 141, 150 and 235of the sequence of the head region of influenza B HA as contactresidues.

The epitope or epitopes recognized by the antibody or antigen bindingfragment thereof of the invention may have a number of uses. Forexample, the epitope in purified or synthetic form can be used to raiseimmune responses (i.e., as a vaccine, or for the production ofantibodies for other uses) or for screening sera for antibodies thatimmunoreact with the epitope. In one embodiment, an epitope recognizedby the antibody or antigen binding fragment thereof of the invention, oran antigen having such an epitope may be used as a vaccine for raisingan immune response. In another embodiment, the antibodies and antigenbinding fragments of the invention can be used to monitor the quality ofvaccines, for example, by determining whether the antigen in a vaccinecontains the correct immunogenic epitope in the correct conformation.

Variable Regions

As used herein, the term “parent antibody” refers to an antibody whichis encoded by an amino acid sequence used for the preparation of avariant or derivative, defined herein. The parent polypeptide mayinclude a native antibody sequence (i.e., a naturally occurring,including a naturally occurring allelic variant) or an antibody sequencewith pre-existing amino acid sequence modifications (such as otherinsertions, deletions and/or substitutions) of a naturally occurringsequence. The parent antibody may be a humanized antibody or a humanantibody. In one embodiment, antibodies of the invention are variants ofa parent antibody. As used herein, the term “variant” refers to anantibody that differs in amino acid sequence from a “parent” antibodyamino acid sequence by virtue of addition, deletion and/or substitutionof one or more amino acid residue(s) in the parent antibody sequence.

The antigen-binding portion of an antibody includes one or morefragments of an antibody that retain the ability to specifically bind toan antigen. It has been shown that the antigen-binding function of anantibody can be performed by fragments of a full-length antibody.Examples of antigen binding fragments encompassed within the term“antigen-binding portion” of an antibody include (i) a Fab fragment, amonovalent fragment that includes the VL, VH, CL and CH1 domains; (ii) aF(ab′)2 fragment, a bivalent fragment that includes two Fab fragmentslinked by a disulfide bridge at the hinge region; (iii) a Fd fragmentthat includes the VH and CH1 domains; (iv) a Fv fragment that includesthe VL and VH domains of a single arm of an antibody, (v) a dAb fragment(Ward et al. (1989) Nature. 341:544-546), which includes a VH domain;and (vi) an isolated complementarity determining region (CDR).Furthermore, although the two domains of the Fv fragment, VL and VH, arecoded for by separate genes, they can be joined, using recombinantmethods, by a synthetic linker that enables them to be made as a singleprotein chain in which the VL and VH regions pair to form monovalentmolecules (known as single chain Fv (scFv); see e.g., Bird et al. (1988)Science. 242:423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci.USA 85:5879-5883). Such single chain antibodies are also intended to beencompassed within the term “antigen-binding portion” of an antibody.These antibody fragments are obtained using conventional techniquesknown to those with skill in the art, and the fragments are screened forutility in the same manner as are intact antibodies. Antigen-bindingportions can be produced by recombinant DNA techniques, or by enzymaticor chemical cleavage of intact immunoglobulins. Antibodies of theinvention include at least one antigen binding domain, which include aVH and a VL domain described herein. Exemplary VH and VL domains areshown in Table 1, below.

TABLE 1 VH and VL domains VH (DNA) VL (DNA) VH (AA) VL (AA) SEQ ID NO:SEQ ID NO: SEQ ID NO: SEQ ID NO: FBD-56 1 6 2 7 FBD-94 11 16 12 17FBC-39 21 26 22 27 FBC-39 LSL 31 36 32 37 FBC-39 FSL 41 46 42 47 FBC-39LTL 51 56 52 57 FBC-39 FTL 61 66 62 67 FBC-39-FSS 73 81 74 82 FBC-39-LTS89 97 90 98 FBC-39-FTS 105 113 106 114

In certain embodiments, the purified antibodies include a VH and/or VLthat has a given percent identify to at least one of the VH and/or VLsequences disclosed herein. As used herein, the term “percent (%)sequence identity”, also including “homology” is defined as thepercentage of amino acid residues or nucleotides in a candidate sequencethat are identical with the amino acid residues or nucleotides in thereference sequences, such as parent antibody sequence, after aligningthe sequences and introducing gaps, if necessary, to achieve the maximumpercent sequence identity, and not considering any conservativesubstitutions as part of the sequence identity. Optimal alignment of thesequences for comparison may be produced, besides manually, by means ofthe local homology algorithm of Smith and Waterman (1981) Ads App. Math.2:482, by means of the local homology algorithm of Neddleman and Wunsch(1970) J. Mol. Biol. 48:443, by means of the similarity search method ofPearson and Lipman (1988) Proc. Natl Acad. Sci. USA 85:2444, or by meansof computer programs which use these algorithms (GAP, BESTFIT, FASTA,BLAST P, BLAST N and TFASTA in Wisconsin Genetics Software Package,Genetics Computer Group, 575 Science Drive, Madison, Wis.).

Antibodies of the invention may include a VH amino acid sequence havingat least 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% identity to the VHamino acid sequences described herein. In another embodiment, antibodiesof the invention may have a VH amino acid sequence having at least, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to theamino acid sequence of the VH amino acid sequences described herein.

Antibodies of the invention may include a VL amino acid sequence havingat least 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% identity to the VLamino acid sequences described herein. In another embodiment, antibodiesof the invention may have a VL amino acid sequence having at least, 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity to the VLamino acid sequences described herein.

Complementarity Determining Regions (CDRs)

While the variable domain (VH and VL) includes the antigen-bindingregion; the variability is not evenly distributed through the variabledomains of antibodies. It is concentrated in segments calledComplementarity Determining Regions (CDRs), both in the light chain (VLor VK) and the heavy chain (VH) variable domains. The more highlyconserved portions of the variable domains are called the frameworkregions (FR). The variable domains of native heavy and light chains eachinclude four FR, largely adopting a β-sheet configuration, connected bythree CDRs, which form loops connecting, and in some cases forming partof, the β-sheet structure. The CDRs in each chain are held together inclose proximity by the FR and, with the CDRs from the other chain,contribute to the formation of the antigen-binding site of antibodies.The three CDRs of the heavy chain are designated HCDR-1, HCDR-2, andHCDR-3, and the three CDRs of the light chain are designated LCDR-1,LCDR-2, and LCDR-3.

In one embodiment, the amino acids in the variable domain,complementarity determining region (CDRs) and framework regions (FR) ofan antibody can be identified following Kabat et al. (1991) Sequences ofProteins of Immunological Interest, 5th Ed. Public Health Service,National Institutes of Health, Bethesda, MD. Using this numberingsystem, the actual linear amino acid sequence may contain fewer oradditional amino acids corresponding to a shortening of, or insertioninto, a FR or CDR of the variable domain. For example, a heavy chainvariable domain may include a single amino acid insertion (residue 52aaccording to Kabat) after residue 52 of H2 and inserted residues (e.g.residues 82a, 82b, and 82c, etc., according to Kabat) after heavy chainFR residue 82. The Kabat numbering of residues may be determined for agiven antibody by alignment at regions of homology of the sequence ofthe antibody with a “standard” Kabat numbered sequence. Maximalalignment of framework residues often requires the insertion of “spacer”residues in the numbering system. In addition, the identity of certainindividual residues at any given Kabat site number may vary fromantibody chain to antibody chain due to interspecies or allelicdivergence.

According to the Kabat et al. numbering system, HCDR-1 begins atapproximately amino acid 31 (i.e., approximately 9 residues after thefirst cysteine residue), includes approximately 5-7 amino acids, andends at the next tyrosine residue. HCDR-2 begins at the fifteenthresidue after the end of CDR-H1, includes approximately 16-19 aminoacids, and ends at the next arginine or lysine residue. HCDR-3 begins atapproximately the thirty third amino acid residue after the end ofHCDR-2; includes 3-25 amino acids; and ends at the sequence W-G-X-G,where X is any amino acid. LCDR-1 begins at approximately residue 24(i.e., following a cysteine residue); includes approximately 10-17residues; and ends at the next tyrosine residue. LCDR-2 begins atapproximately the sixteenth residue after the end of LCDR-1 and includesapproximately 7 residues. LCDR-3 begins at approximately the thirtythird residue after the end of LCDR-2; includes approximately 7-11residues and ends at the sequence F-G-X-G, where X is any amino acid.Note that CDRs vary considerably from antibody to antibody (and bydefinition will not exhibit homology with the Kabat consensussequences). CDR heavy chain and light chain sequences of antibodies ofthe invention, numbered using the Kabat system are shown in Tables 2 and3, below.

TABLE 2 HCDR-1-3, as identified by Kabat et al. HCDR-1 HCDR-2 HCDR-3 SEQID NO: SEQ ID NO: SEQ ID NO: FBD-56 3 4 5 FBD-94 13 14 15 FBC-39 23 2425 FBC-39 LSL 33 34 35 FBC-39 FSL 43 44 45 FBC-39 LTL 53 54 55 FBC-39FTL 63 64 65 FBC-39-FSS 75 76 77 FBC-39-LTS 91 92 93 FBC-39-FTS 107 108109

TABLE 3 LCDR-1-3, as identified by Kabat et al. LCDR-1 LCDR-2 LCDR-3 SEQID NO: SEQ ID NO: SEQ ID NO: FBD-56 8 9 10 FBD-94 18 19 20 FBC-39 28 2930 FBC-39 LSL 38 39 40 FBC-39 FSL 48 49 50 FBC-39 LTL 58 59 60 FBC-39FTL 68 69 70 FBC-39-FSS 83 84 85 FBC-39-LTS 99 100 101 FBC-39-FTS 115116 117

Although the Kabat numbering scheme is widely used, it has someshortcomings. First, since the numbering scheme was developed fromsequence data, in the absence of structural information, the position atwhich insertions occur in LCDR-1 and HCDR-1 does not always match thestructural insertion position. Thus, topologically equivalent residuesin these loops may not receive the same number. Second, the numberingsystem is rigid, allowing only for a limited number of insertions. Ifthere are more residues than the allotted numbering system forinsertions, there is no standard way of numbering them.

In another embodiment, the amino acids in the variable domain,complementarity determining regions (CDRs) and framework regions (FR) ofan antibody can be identified using the Immunogenetics (IMGT) database(http://imgt.cines.fr). Lefranc et al. (2003) Dev Comp Immunol.27(1):55-77. The IMGT database was developed using sequence informationfor immunoglobulins (IgGs), T-cell receptors (TcR) and MajorHistocompatibility Complex (MHC) molecules and unifies numbering acrossantibody lambda and kappa light chains, heavy chains and T-cell receptorchains and avoids the use of insertion codes for all but uncommonly longinsertions. IMGT also takes into account and combines the definition ofthe framework (FR) and complementarity determining regions (CDR) fromKabat et al., the characterization of the hypervariable loops fromChothia et al., as well as structural data from X-ray diffractionstudies. CDR heavy chain and light chain sequences for antibodies of theinvention, numbered using the IMGT system, are shown in Tables 4 and 5,below. FIG. 5 provides an alignment of the FBD-56, FBD-94 and FBC-39sequences showing the CDR sequences as identified by Kabat, and IMGT.

TABLE 4 HCDR-1-3, as identified by IMGT HCDR-1 HCDR-2 HCDR-3 SEQ ID NO:SEQ ID NO: SEQ ID NO: FBC-39 121 122 123 FBC-39 LSL 127 128 129 FBC-39FSL 133 134 135 FBC-39 LTL 139 140 141 FBC-39 FTL 145 146 147 FBC-39-FSS78 79 80 FBC-39-LTS 94 95 96 FBC-39-FTS 110 111 112

TABLE 5 LCDR-1-3, as identified by IMGT LCDR-1 LCDR-2 LCDR-3 SEQ ID NO:SEQ ID NO: SEQ ID NO: FBC-39 124 125 126 FBC-39 LSL 130 131 132 FBC-39FSL 136 137 138 FBC-39 LTL 142 143 144 FBC-39 FTL 148 149 150 FBC-39-FSS86 87 88 FBC-39-LTS 102 103 104 FBC-39-FTS 118 119 120

The present invention encompasses neutralizing anti-influenza Bantibodies that include amino acids in a sequence that is at least 75%,80%, 85%, 90%, 95% or 100% identical to an amino acid sequence of a VHof SEQ ID NO.: 2; SEQ ID NO.: 12; SEQ ID NO.: 22; SEQ ID NO.: 32; SEQ IDNO.: 42; SEQ ID NO.: 52; SEQ ID NO.: 62; SEQ ID NO.: 74; SEQ ID NO.: 90;or SEQ ID NO.: 106; and/or at least 75%, 80%, 85%, 90%, 95% or 100%identical to an amino acid sequence of a VL of SEQ ID NO.: 7; SEQ IDNO.: 17; SEQ ID NO.: 27; SEQ ID NO.: 37; SEQ ID NO.: 47; SEQ ID NO.: 57;SEQ ID NO.: 67; SEQ ID NO.: 82; SEQ ID NO.: 98; or SEQ ID NO.: 114. Inanother embodiment, the present invention encompasses neutralizinganti-influenza B antibodies that include amino acids in a sequence thatis at least 95%, 96%, 97%, 98%, 99% or 100% identical to an amino acidsequence of a VH of SEQ ID NO.: 2; SEQ ID NO.: 12; SEQ ID NO.: 22; SEQID NO.: 32; SEQ ID NO.: 42; SEQ ID NO.: 52; SEQ ID NO.: 62; SEQ ID NO.:74; SEQ ID NO.: 90; or SEQ ID NO.: 106; and/or at least 95%, 96%, 97%,98%, 99% or 100% identical to an amino acid sequence of a VL of SEQ IDNO.: 7; SEQ ID NO.: 17; SEQ ID NO.: 27; SEQ ID NO.: 37; SEQ ID NO.: 47;SEQ ID NO.: 57; SEQ ID NO.: 67; SEQ ID NO.: 82; SEQ ID NO.: 98; or SEQID NO.: 114.

In another embodiment, invention provides antibodies and antigen bindingfragments thereof that include a set of six CDRs: HCDR-1, HCDR-2,HCDR-3, LCDR-1, LCDR-2, LCDR-3, wherein CDRs are selected from the HCDRsand LCDRs shown in Tables 2 through 5. In another embodiment, theinvention provides antibodies and antigen binding fragments thereof thatinclude a set of six CDRs: HCDR-1, HCDR-2, HCDR-3, LCDR-1, LCDR-2,LCDR-3, wherein CDRs include amino acids in a sequence that is at least75%, 80%, 85%, 90%, 95% or 100% identical to an amino acid sequence ofthe HCDRs and LCDRs shown in Tables 2 through 5. In another embodiment,the invention provides antibodies and antigen binding fragments thereofthat include a set of six CDRs: HCDR-1, HCDR-2, HCDR-3, LCDR-1, LCDR-2,LCDR-3, wherein CDRs include amino acids in a sequence that is at least95%, 96%, 97%, 98%, 99% or 100% identical to an amino acid sequence ofthe HCDRs and LCDRs shown in Tables 2 through 5.

Framework Regions

The variable domains of the heavy and light chains each include fourframework regions (FR1, FR2, FR3, FR4), which are the more highlyconserved portions of the variable domains. The four FRs of the heavychain are designated FR-H1, FR-H2, FR-H3 and FR-H4, and the four FRs ofthe light chain are designated FR-L1, FR-L2, FR-L3 and FR-L4.

In one embodiment, the Kabat numbering system can be used to identifythe framework regions. According to Kabat et al., FR-H1 begins atposition 1 and ends at approximately amino acid 30, FR-H2 isapproximately from amino acid 36 to 49, FR-H3 is approximately fromamino acid 66 to 94 and FR-H4 is approximately amino acid 103 to 113.FR-L1 begins at amino acid 1 and ends at approximately amino acid 23,FR-L2 is approximately from amino acid 35 to 49, FR-L3 is approximatelyfrom amino acid 57 to 88 and FR-L4 is approximately from amino acid 98to 107. In certain embodiments the framework regions may containsubstitutions according to the Kabat numbering system, e.g., insertionat 106A in FR-L1. In addition to naturally occurring substitutions, oneor more alterations (e.g., substitutions) of FR residues may also beintroduced in an antibody of the invention, provided it retainsneutralizing ability. In certain embodiments, these result in animprovement or optimization in the binding affinity of the antibody forinfluenza B virus HA. Examples of framework region residues to modifyinclude those which non-covalently bind antigen directly (Amit et al.(1986) Science. 233:747-753); interact with/effect the conformation of aCDR (Chothia et al. (1987) J. Mol. Biol. 196:901-917); and/orparticipate in the VL-VH interface (U.S. Pat. No. 5,225,539). In otherembodiments, the framework regions can be identified using the numberingsystem of IMGT.

In another embodiment the FR may include one or more amino acid changesfor the purposes of “germlining”. For example, the amino acid sequencesof selected antibody heavy and light chains can be compared to germlineheavy and light chain amino acid sequences; where certain frameworkresidues of the selected VL and/or VH chains differ from the germlineconfiguration (e.g., as a result of somatic mutation of theimmunoglobulin), it may be desirable to “back-mutate” the alteredframework residues of the selected antibodies to the germlineconfiguration (i.e., change the framework amino acid sequences of theselected antibodies so that they are the same as the germline frameworkamino acid sequences), for example, to reduce the chance ofimmunogenicity. Such “back-mutation” (or “germlining”) of frameworkresidues can be accomplished by standard molecular biology methods forintroducing specific mutations (e.g., site-directed mutagenesis;PCR-mediated mutagenesis, and the like).

FIG. 6 shows the amino acid sequence of the VH domain of a genericizedanti-influenza B antibody (SEQ ID NO:71) in which non-germline residuesin FBC-39 (SEQ ID NO: 22) are designated as In one embodiment, one ormore of the non-germline (Xaa₁₋₁₁) residues are “back-mutated” togermline. In one embodiment, Xaa₁ of SEQ ID NO: 71 is Val or Glu; Xaa₂of SEQ ID NO: 71 is Leu or Phe; Xaa₃ of SEQ ID NO: 71 is Ser or Thr;Xaa₄ of SEQ ID NO: 71 is Leu or Ser; Xaa₅ of SEQ ID NO: 71 is Ser orThr; Xaa₆ of SEQ ID NO: 71 is Met or Thr; Xaa₇ of SEQ ID NO: 71 is Pheor Tyr; Xaa₈ of SEQ ID NO: 71 is His or Gln; Xaa₉ of SEQ ID NO: 71 isSer or Asn; Xaa₁₀ of SEQ ID NO: 71 is Arg or Lys; and Xaa₁₁ of SEQ IDNO: 71 is Ala or Thr. In another embodiment, Xaa₁ of SEQ ID NO:71 isGlu; Xaa₅ of SEQ ID NO:71 is Thr; Xaa₆ of SEQ ID NO:71 is Thr; Xaa₇ ofSEQ ID NO:71 is Tyr; Xaa₈ of SEQ ID NO:71 is Gln; Xaa₁₀ of SEQ ID NO:71is Lys; Xaa₁₁ of SEQ ID NO:71 is Thr, or combinations thereof. In a moreparticular embodiment, Xaa₉ of SEQ ID NO:71 is Ser. In yet anotherembodiment, Xaa₄ of SEQ ID NO:71 is Leu.

FIG. 7 shows an amino acid sequence of the VL domain of a genericizedanti-influenza B antibody (SEQ ID NO:72), in which non-germline residuesin FBC-39 (SEQ ID NO: 27) are represented by Xaa₁. In one embodiment,the non-germline residue (Xaa₁) is “back-mutated” to germline. In oneembodiment, Xaa₁ of SEQ ID NO:72 is Phe or Tyr. In a more particularembodiment, Xaa₁ of SEQ ID NO:72 is Tyr.

Nucleotide Sequences Encoding Antibodies of the Invention

In addition to the amino acid sequences described above, the inventionfurther provides nucleotide sequences corresponding to the amino acidsequences and encoding the human antibodies of the invention. In oneembodiment, the invention provides polynucleotides that include anucleotide sequence encoding an antibody described herein or fragmentsthereof. These include, but are not limited to, nucleotide sequencesthat code for the above referenced amino acid sequences. Thus, thepresent invention also provides polynucleotide sequences encoding VH andVL framework regions including CDRs and FRs of antibodies describedherein as well as expression vectors for their efficient expression incells (e.g. mammalian cells). Methods of making the antibodies usingpolynucleotides are described below in more detail.

The invention also encompasses polynucleotides that hybridize understringent or lower stringency hybridization conditions, e.g., as definedherein, to polynucleotides that encode an antibody of the inventiondescribed herein. The term “stringency” as used herein refers toexperimental conditions (e.g. temperature and salt concentration) of ahybridization experiment to denote the degree of homology between theprobe and the filter bound nucleic acid; the higher the stringency, thehigher percent homology between the probe and filter bound nucleic acid.

Stringent hybridization conditions include, but are not limited to,hybridization to filter-bound DNA in 6× sodium chloride/sodium citrate(SSC) at about 45° C. followed by one or more washes in 0.2×SSC/0.1% SDSat about 50-65° C., highly stringent conditions such as hybridization tofilter-bound DNA in 6×SSC at about 45° C. followed by one or more washesin 0.1×SSC/0.2% SDS at about 65° C., or any other stringenthybridization conditions known to those skilled in the art (see, forexample, Ausubel et al., eds. (1989) Current Protocols in MolecularBiology, vol. 1, Green Publishing Associates, Inc. and John Wiley andSons, Inc., NY at pages 6.3.1 to 6.3.6 and 2.10.3).

Substantially identical sequences may be polymorphic sequences, i.e.,alternative sequences or alleles in a population. An allelic differencemay be as small as one base pair. Substantially identical sequences mayalso include mutagenized sequences, including sequences having silentmutations. A mutation may include one or more residue changes, adeletion of one or more residues, or an insertion of one or moreadditional residues.

The polynucleotides may be obtained, and the nucleotide sequence of thepolynucleotides determined, by any method known in the art. For example,if the nucleotide sequence of the antibody is known, a polynucleotideencoding the antibody may be assembled from chemically synthesizedoligonucleotides (e.g., as described in Kutmeier et al. (1994)BioTechniques. 17:242), which, briefly, involves the synthesis ofoverlapping oligonucleotides containing portions of the sequenceencoding the antibody, annealing and ligating of those oligonucleotides,and then amplification of the ligated oligonucleotides by PCR.

A polynucleotide encoding an antibody may also be generated from nucleicacid from a suitable source. If a clone containing a nucleic acidencoding a particular antibody is not available, but the sequence of theantibody molecule is known, a nucleic acid encoding the immunoglobulinmay be chemically synthesized or obtained from a suitable source (e.g.,an antibody cDNA library, or a cDNA library generated from, or nucleicacid, in one embodiment polyA+RNA, isolated from, any tissue or cellsexpressing the antibody, such as hybridoma cells selected to express anantibody) by PCR amplification using synthetic primers hybridizable tothe 3′ and 5′ ends of the sequence or by cloning using anoligonucleotide probe specific for the particular gene sequence toidentify, e.g., a cDNA clone from a cDNA library that encodes theantibody. Amplified nucleic acids generated by PCR may then be clonedinto replicable cloning vectors using any method well known in the art.

Once the nucleotide sequence and corresponding amino acid sequence ofthe antibody is determined, the nucleotide sequence of the antibody maybe manipulated using methods well known in the art for the manipulationof nucleotide sequences, e.g., recombinant DNA techniques, site directedmutagenesis, PCR, etc. (see, for example, the techniques described inSambrook et al. (1990) Molecular Cloning, A Laboratory Manual, 2d Ed.,Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. and Ausubel etal. eds. (1998) Current Protocols in Molecular Biology, John Wiley &Sons, NY), to generate antibodies having a different amino acidsequence, for example to create amino acid substitutions, deletions,and/or insertions.

Binding Characteristics

As described above, the antibodies or antigen binding fragments of theinvention immunospecifically bind at least one specified epitope orantigenic determinant of influenza B virus HA protein, peptide, subunit,fragment, portion or any combination thereof either exclusively orpreferentially with respect to other polypeptides. In a specificembodiment, the epitope or antigenic determinant of influenza B virus HAprotein is the globular head. The term “epitope” or “antigenicdeterminant” as used herein refers to a protein determinant capable ofbinding to an antibody. In one embodiment, the term “binding” hereinrelates to specific binding. These protein determinants or epitopesusually include chemically active surface groupings of molecules such asamino acids or sugar side chains and usually have a specific threedimensional structural characteristics, as well as specific chargecharacteristics. Conformational and non-conformational epitopes aredistinguished in that the binding to the former but not the latter islost in the presence of denaturing solvents. The term “discontinuousepitope” as used herein, refers to a conformational epitope on a proteinantigen which is formed from at least two separate regions in theprimary sequence of the protein.

The interactions between antigens and antibodies are the same as forother non-covalent protein-protein interactions. In general, four typesof binding interactions exist between antigens and antibodies: (i)hydrogen bonds, (ii) dispersion forces, (iii) electrostatic forcesbetween Lewis acids and Lewis bases, and (iv) hydrophobic interactions.Hydrophobic interactions are a major driving force for theantibody-antigen interaction, and are based on repulsion of water bynon-polar groups rather than attraction of molecules (Tanford, (1978)Science. 200:1012-8). However, certain physical forces also contributeto antigen-antibody binding, for example, the fit or complimentary ofepitope shapes with different antibody binding sites. Moreover, othermaterials and antigens may cross-react with an antibody, therebycompeting for available free antibody.

Measurement of the affinity constant and specificity of binding betweenantigen and antibody can assist in determining the efficacy ofprophylactic, therapeutic, diagnostic and research methods using theantibodies of the invention. “Binding affinity” generally refers to thestrength of the sum total of the noncovalent interactions between asingle binding site of a molecule (e.g., an antibody) and its bindingpartner (e.g., an antigen). Unless indicated otherwise, as used herein,“binding affinity” refers to intrinsic binding affinity which reflects a1:1 interaction between members of a binding pair (e.g., antibody andantigen). The affinity of a molecule X for its partner Y can generallybe represented by the equilibrium dissociation constant (Kd), which iscalculated as the ratio k_(off)/k_(on). See, e.g., Chen et al. (1999) J.Mol Biol. 293:865-881. Low-affinity antibodies generally bind antigenslowly and tend to dissociate readily, whereas high-affinity antibodiesgenerally bind antigen faster and tend to remain bound longer. A varietyof methods of measuring binding affinity are known in the art, any ofwhich can be used for purposes of the present invention.

One method for determining binding affinity includes measuring thedisassociation constant “Kd” by a radiolabeled antigen binding assay(RIA) performed with the Fab version of an antibody of interest and itsantigen as described by Chen et al. (1999) J. Mol Biol. 293:865-881.Alternately, the Kd value may be measured by using surface plasmonresonance assays using a BIAcore™-2000 or a BIAcore™-3000 (BIAcore,Inc., Piscataway, N.J.). If the on-rate exceeds 10⁶ M⁻¹ S⁻¹ by thesurface plasmon resonance assay, then the on-rate can be determined byusing a fluorescent quenching technique that measures the increase ordecrease in fluorescence emission intensity in the presence ofincreasing concentrations of antigen. An “on-rate” or “rate ofassociation” or “association rate” or “k_(on)” can also be determinedwith the same surface plasmon resonance technique described above.

Methods and reagents suitable for determination of bindingcharacteristics of an antibody of the present invention, or analtered/mutant derivative thereof, are known in the art and/or arecommercially available (U.S. Pat. Nos. 6,849,425; 6,632,926; 6,294,391;6,143,574). Moreover, equipment and software designed for such kineticanalyses are commercially available (e.g. Biacore® A100, and Biacore®2000 instruments; Biacore International AB, Uppsala, Sweden).

In one embodiment, antibodies of the present invention, includingantigen binding fragments or variants thereof, may also be described orspecified in terms of their binding affinity for influenza A viruspolypeptides; influenza B virus polypeptides; or a combination thereof.Typically, antibodies with high affinity have Kd of less than 10⁻⁷ M. Inone embodiment, antibodies or antigen binding fragments thereof bindinfluenza A polypeptides; influenza B polypeptides; fragments orvariants thereof; or a combination thereof, with a dissociation constantor Kd of less than or equal to 5×10⁻⁷ M, 10⁻⁷ M, 5×10⁻⁸ M, 10⁻⁶ M,5×10⁻⁹ M, 10⁻⁹ M, 5×10⁻¹⁰ M, 10⁻¹⁰ M, 5×10⁻¹¹ M, 10⁻¹¹ M, 5×10⁻¹² M,10⁻¹² M, 5×10⁻¹³ M, 10⁻¹³ M, 5×10⁻¹⁴ M, 10⁻¹⁴ M, 5×10⁻¹⁵ M or 10⁻¹⁵ M.In a more particular embodiment, antibodies or antigen binding fragmentsthereof bind influenza A polypeptides; influenza B polypeptides,fragments or variants thereof; or combinations thereof, with adissociation constant or Kd of less than or equal to 5×10⁻¹⁰M, 10⁻¹⁰ M,5×10⁻¹¹ M, 10⁻¹¹ M, 5×10⁻¹² M or 10⁻¹² M. The invention encompassesantibodies that bind influenza A polypeptides; influenza B polypeptides;or a combination thereof, with a dissociation constant or Kd that iswithin a range between any of the individual recited values.

In another embodiment, antibodies or antigen binding fragments thereofof the invention bind influenza A polypeptides; influenza Bpolypeptides; fragments or variants thereof; or combinations thereof,with an off rate (k_(off)) of less than or equal to 5×10⁻² sec⁻¹, 10⁻²sec⁻¹, 5×10⁻³ sec⁻¹ or 10⁻³ sec⁻¹, 5×10⁻⁴ sec⁻¹, 10⁻⁴ sec⁻¹, 5×10⁻⁵sec⁻¹, or 10⁻⁵ sec⁻¹, 5×10⁻⁶ sec⁻¹, 10⁻⁶ sec⁻¹, 5×10⁻⁷ sec⁻¹ or 10⁻⁷sec⁻¹. In a more particular embodiment, antibodies or antigen bindingfragments thereof of the invention bind influenza A polypeptides orfragments or variants thereof with an off rate (k_(off)) less than orequal to 5×10⁻⁴ sec⁻¹, 10⁻⁴ sec⁻¹, 5×10⁻⁵ sec⁻¹, or 10⁻⁵ sec⁻¹, 5×10⁻⁶sec⁻¹, 10⁻⁶ sec⁻¹, 5×10⁻⁷ sec⁻¹ or 10⁻⁷ sec⁻¹. The invention alsoencompasses antibodies that bind influenza A polypeptides; influenza Bpolypeptides; or combinations thereof, with an off rate (k_(off)) thatis within a range between any of the individual recited values.

In another embodiment, antibodies or antigen binding fragments thereofof the invention bind influenza A polypeptides; influenza Bpolypeptides; fragments or variants thereof; or combinations thereof,with an on rate (k_(on)) of greater than or equal to 10³ M⁻¹ sec⁻¹,5×10³ M⁻¹ sec⁻¹, 10⁴ M⁻¹ sec⁻¹, 5×10⁴ M⁻¹ sec⁻¹, 10⁵ M⁻¹ sec⁻¹, 5×10⁵M⁻¹ sec⁻¹, 10⁶ M⁻¹ sec-1, 5×10⁶ M⁻¹ sec⁻¹, 10⁷ M⁻¹ sec-1, or 5×10⁷ M⁻¹sec⁻¹. In a more particular embodiment, antibodies or antigen bindingfragments thereof of the invention bind influenza A polypeptides;influenza B polypeptides; fragments or variants thereof; or combinationsthereof, with an on rate (k_(on)) greater than or equal to 10⁵ M⁻¹sec⁻¹, 5×10⁵ M⁻¹ sec⁻¹, 10⁶ M⁻¹ sec-1, 5×10⁶ M⁻¹ sec⁻¹, 10⁷ M⁻¹ sec⁻¹ or5×10⁷ M⁻¹ sec⁻¹. The invention encompasses antibodies that bindinfluenza A polypeptides; influenza B polypeptides; or combinationsthereof, with on rate (k_(on)) that is within a range between any of theindividual recited values.

In one embodiment, a binding assay may be performed either as a directbinding assay or as a competition-binding assay. Binding can be detectedusing standard ELISA or standard Flow Cytometry assays. In a directbinding assay, a candidate antibody is tested for binding to its cognateantigen. Competition-binding assay, on the other hand, assess theability of a candidate antibody to compete with a known antibody orother compound that binds to a particular antigen, for example,influenza B virus HA. In general any method that permits the binding ofan antibody with the influenza B virus HA that can be detected isencompassed with the scope of the present invention for detecting andmeasuring the binding characteristics of the antibodies. One of skill inthe art will recognize these well-known methods and for this reason arenot provided in detail here. These methods are also utilized to screen apanel of antibodies for those providing the desired characteristics.

In one embodiment, an antibody of the invention immunospecifically bindsto influenza B virus HA and is capable of neutralizing influenza B virusinfection. In one embodiment, an antibody of the inventionimmunospecifically binds to at least one Yamagata lineage influenza Bvirus and at least one Victoria lineage influenza B virus. In anotherembodiment, an antibody of the invention immunospecifically bindsYamagata lineage and Victoria lineage influenza B virus.

In another embodiment, an antibody of the invention immunospecificallybinds to influenza B virus HA and influenza A virus HA and is capable ofneutralizing influenza B virus and influenza A virus infection. In oneembodiment, an antibody of the invention immunospecifically binds to atleast one Yamagata lineage influenza B virus; at least one Victorialineage influenza B virus and at least one influenza A virus subtype.

The hemagglutinin subtypes of influenza A viruses fall into two majorphylogenetic groupings, identified as group 1, which includes subtypesH1, H2, H5, H6, H8, H9, H11, H12, H13, H16 and H17 and group 2, whichincludes subtypes H3, H4, H7, H10, H14, and H15. In one embodiment, anantibody or antigen binding fragment according to the invention iscapable of binding to and/or neutralizing one or more influenza A virusgroup 1 subtypes selected from H8, H9, H11, H12, H13, H16 and H17 andvariants thereof. In another embodiment, an antibody or antigen bindingfragment according to the invention is capable of binding to and/orneutralizing one or more influenza A virus group 2 subtypes selectedfrom H4, H10, H14 and H15 and variants thereof. In one embodiment, theantibody of the invention binds to influenza A virus group 1 subtype H9.In one embodiment, the antibody of the invention binds to andneutralizes influenza A virus group 1 subtype H9.

In one embodiment, the antibody of the invention immunospecificallybinds to influenza B virus HA and is capable of neutralizing influenza Bvirus infection. In another embodiment, the antibody of the inventionimmunospecifically binds to influenza A and influenza B virus HA and iscapable of neutralizing influenza A and influenza B virus infection.Neutralization assays can be performed as described herein in theExamples section or using other methods known in the art. The term“inhibitory concentration 50%” (abbreviated as “IC₅₀”) represents theconcentration of an inhibitor (e.g., an antibody of the invention) thatis required for 50% neutralization of influenza A and/or influenza Bvirus. It will be understood by one of ordinary skill in the art that alower IC₅₀ value corresponds to a more potent inhibitor.

In one embodiment, an antibody or antigen binding fragment thereofaccording to the invention has an IC₅₀ for neutralizing influenza Bvirus in the range of from about 0.001 μg/ml to about 5 μg/ml, or in therange of from about 0.001 μg/ml to about 1 μg/ml of antibody, or lessthan 5 μg/ml, less than 2 μg/ml, less than 1 μg/ml, less than 0.5 μg/ml,less than 0.1 μg/ml, less than 0.05 μg/ml or less than 0.01 μg/ml in amicroneutralization assay.

In one embodiment, an antibody or antigen binding fragment thereofaccording to the invention has an IC₅₀ for neutralizing influenza Bvirus in the range of from about 0.001 μg/ml to about 5 μg/ml, or in therange of from about 0.001 μg/ml to about 1 μg/ml of antibody, or lessthan 5 μg/ml, less than 2 μg/ml, less than 1 μg/ml, less than 0.5 μg/ml,less than 0.1 μg/ml, less than 0.05 μg/ml or less than 0.01 μg/ml in amicroneutralization assay; and an IC₅₀ for neutralizing influenza Avirus in the range of from about 0.1 μg/ml to about 5 μg/ml, or in therange of from about 0.1 μg/ml to about 2 μg/ml of antibody, or less than5 μg/ml, less than 2 μg/ml, less than 1 μg/ml, or less than 0.5 μg/mlfor neutralization of influenza A virus in a microneutralization assay.

In one embodiment, an antibody or antigen binding fragment thereofaccording to the invention has an IC₅₀ for neutralizing influenza Bvirus in the range of from about 0.001 μg/ml to about 50 μg/ml, or inthe range of from about 0.001 μg/ml to about 5 μg/ml of antibody, or inthe range of from about 0.001 μg/ml to about 1 μg/ml of antibody, orless than 10 μg/ml, less than 5 μg/ml, less than 1 μg/ml, less than 0.5μg/ml, less than 0.1 μg/ml, less than 0.05 μg/ml or less than 0.01 μg/mlin a microneutralization assay; and an IC₅₀ for neutralizing influenza Avirus in the range of from about 0.01 μg/ml to about 50 μg/ml, or in therange of from about 0.05 μg/ml to about 5 μg/ml of antibody, or in therange of from about 0.1 μg/ml to about 2 μg/ml of antibody, or less than50 μg/ml, less than 25 μg/ml, less than 10 μg/ml, less than 5 μg/ml, orless than 2 μg/ml for neutralization of influenza A virus in amicroneutralization assay.

In certain embodiments, the antibodies of the invention may induce celldeath. An antibody which “induces cell death” is one which causes aviable cell to become nonviable. Cell death in vitro may be determinedin the absence of complement and immune effector cells to distinguishcell death induced by antibody-dependent cell-mediated cytotoxicity(ADCC) or complement dependent cytotoxicity (CDC). Thus, the assay forcell death may be performed using heat inactivated serum (i.e., in theabsence of complement) and in the absence of immune effector cells. Todetermine whether the antibody is able to induce cell death, loss ofmembrane integrity as evaluated by uptake of propidium iodide (PI),trypan blue (see, Moore et al. (1995) Cytotechnology 17:1-11), 7AAD orother methods well known in the art can be assessed relative tountreated cells.

In a specific embodiment, the antibodies of the invention may inducecell death via apoptosis. An antibody which “induces apoptosis” is onewhich induces programmed cell death as determined by binding of annexinV, fragmentation of DNA, cell shrinkage, dilation of endoplasmicreticulum, cell fragmentation, and/or formation of membrane vesicles(called apoptotic bodies). Various methods are available for evaluatingthe cellular events associated with apoptosis. For example, phosphatidylserine (PS) translocation can be measured by annexin binding; DNAfragmentation can be evaluated through DNA laddering; andnuclear/chromatin condensation along with DNA fragmentation can beevaluated by any increase in hypodiploid cells. In one embodiment, theantibody which induces apoptosis is one which results in about 2 to 50fold, in one embodiment about 5 to 50 fold, and in one embodiment about10 to 50 fold, induction of annexin binding relative to untreated cellin an annexin binding assay.

In another specific embodiment, the antibodies of the invention mayinduce cell death via antibody-dependent cellular cytotoxicity (ADCC)and/or complement-dependent cell-mediated cytotoxicity (CDC) and/orantibody dependent cell-mediated phagocytosis (ADCP). Expression of ADCCactivity and CDC activity of the human IgG1 subclass antibodiesgenerally involves binding of the Fc region of the antibody to areceptor for an antibody (hereinafter referred to as “FcγR”) existing onthe surface of effector cells such as killer cells, natural killer cellsor activated macrophages. Various complement components can be bound.Regarding the binding, it has been suggested that several amino acidresidues in the hinge region and the second domain of C region(hereinafter referred to as “Cγ2 domain”) of the antibody are important(Greenwood et al. (1993) Eur. J. Immunol. 23(5):1098-104; Morgan et al.(1995) Immunology. 86(2):319-324; Clark, M. (1997) Chemical Immunology.65:88-110) and that a sugar chain in the Cγ2 domain (Clark, M. (1997)Chemical Immunology. 65:88-110) is also important.

To assess ADCC activity of an antibody of interest, an in vitro ADCCassay can be used, such as that described in U.S. Pat. No. 5,500,362.The assay may also be performed using a commercially available kit, e.g.CytoTox 96® (Promega). Useful effector cells for such assays include,but are not limited to peripheral blood mononuclear cells (PBMC),Natural Killer (NK) cells, and NK cell lines. NK cell lines expressing atransgenic Fc receptor (e.g. CD16) and associated signaling polypeptide(e.g. FC_(ε)RI-γ) may also serve as effector cells (WO 2006/023148). Inone embodiment, the NK cell line includes CD16 and has luciferase underthe NFAT promoter and can be used to measure NK cell activation, ratherthan cell lysis or cell death. A similar technology is sold by Promega,which uses Jurkat cells instead of NK cells (Promega ADCC reporterbioassay #G7010). For example, the ability of any particular antibody tomediate lysis by complement activation and/or ADCC can be assayed. Thecells of interest are grown and labeled in vitro; the antibody is addedto the cell culture in combination with immune cells which may beactivated by the antigen antibody complexes; i.e., effector cellsinvolved in the ADCC response. The antibody can also be tested forcomplement activation. In either case, cytolysis is detected by therelease of label from the lysed cells. The extent of cell lysis may alsobe determined by detecting the release of cytoplasmic proteins (e.g.LDH) into the supernatant. In fact, antibodies can be screened using thepatient's own serum as a source of complement and/or immune cells.Antibodies that are capable of mediating human ADCC in the in vitro testcan then be used therapeutically in that particular patient. ADCCactivity of the molecule of interest may also be assessed in vivo, e.g.,in an animal model such as that disclosed in Clynes et al. (1998) Proc.Natl. Acad. Sci. USA 95:652-656. Moreover, techniques for modulating(i.e., increasing or decreasing) the level of ADCC, and optionally CDCactivity, of an antibody are well-known in the art (e.g., U.S. Pat. Nos.5,624,821; 6,194,551; 7,317,091). Antibodies of the present inventionmay be capable or may have been modified to have the ability of inducingADCC and/or CDC. Assays to determine ADCC function can be practicedusing human effector cells to assess human ADCC function. Such assaysmay also include those intended to screen for antibodies that induce,mediate, enhance, block cell death by necrotic and/or apoptoticmechanisms. Such methods including assays utilizing viable dyes, methodsof detecting and analyzing caspases, and assays measuring DNA breaks canbe used to assess the apoptotic activity of cells cultured in vitro withan antibody of interest.

Production of Antibodies

The following describes exemplary techniques for the production of theantibodies useful in the present invention.

Monoclonal Antibodies

Monoclonal antibodies can be prepared using a wide variety of techniquesknown in the art including the use of hybridoma (Kohler et al. (1975)Nature. 256:495; Harlow et al. (1988) Antibodies: A Laboratory Manual,(Cold Spring Harbor Laboratory Press, 2nd ed.); Hammerling et al. (1981)in: Monoclonal Antibodies and T-Cell Hybridomas 563-681 (Elsevier,N.Y.), recombinant, and phage display technologies, or a combinationthereof. The term “monoclonal antibody” as used herein refers to anantibody obtained from a population of substantially homogeneous orisolated antibodies, e.g., the individual antibodies that make up thepopulation are identical except for possible naturally occurringmutations that may be present in minor amounts. Monoclonal antibodiesare highly specific, being directed against a single antigenic site.Furthermore, in contrast to polyclonal antibody preparations whichinclude different antibodies directed against different determinants(epitopes), each monoclonal antibody is directed against the samedeterminant on the antigen. In addition to their specificity, monoclonalantibodies are advantageous in that they may be synthesizeduncontaminated by other antibodies. The modifier “monoclonal” is not tobe construed as requiring production of the antibody by any particularmethod. Following is a description of representative methods forproducing monoclonal antibodies which is not intended to be limiting andmay be used to produce, for example, monoclonal mammalian, chimeric,humanized, human, domain, diabodies, vaccibodies, linear andmultispecific antibodies.

Hybridoma Techniques

Methods for producing and screening for specific antibodies usinghybridoma technology are routine and well known in the art. In thehybridoma method, mice or other appropriate host animals, such ashamster, are immunized as described above to elicit lymphocytes thatproduce or are capable of producing antibodies that will specificallybind to the antigen used for immunization. Alternatively, lymphocytesmay be immunized in vitro. After immunization, lymphocytes are isolatedand then fused with a myeloma cell line using a suitable fusing agent orfusion partner, such as polyethylene glycol, to form a hybridoma cell(Goding (1986) Monoclonal Antibodies: Principles and Practice, pp.59-103 (Academic Press)). In certain embodiments, the selected myelomacells are those that fuse efficiently, support stable high-levelproduction of antibody by the selected antibody-producing cells, and aresensitive to a selective medium that selects against the unfusedparental cells. In one aspect, the myeloma cell lines are murine myelomalines, such as those derived from MOPC-21 and MPC-11 mouse tumorsavailable from the Salk Institute Cell Distribution Center, San Diego,Calif. USA, and SP-2 and derivatives e.g., X63-Ag8-653 cells availablefrom the American Type Culture Collection, Rockville, Md. USA. Humanmyeloma and mouse-human heteromyeloma cell lines also have beendescribed for the production of human monoclonal antibodies (Kozbor(1984) J. Immunol. 133:3001; and Brodeur et al. (1987) MonoclonalAntibody Production Techniques and Applications, pp.51-63 (MarcelDekker, Inc., New York). Once hybridoma cells that produce antibodies ofthe desired specificity, affinity, and/or activity are identified, theclones may be subcloned by limiting dilution procedures and grown bystandard methods (Goding, Supra). Suitable culture media for thispurpose include, for example, D-MEM or RPMI-1640 medium. In addition,the hybridoma cells may be grown in vivo as ascites tumors in an animale.g., by i.p. injection of the cells into mice.

The monoclonal antibodies secreted by the sub-clones are suitablyseparated from the culture medium, ascites fluid, or serum byconventional antibody purification procedures such as, for example,affinity chromatography (e.g., using protein A or protein G-Sepharose)or ion-exchange chromatography, affinity tags, hydroxylapatitechromatography, gel electrophoresis, dialysis, etc. Exemplarypurification methods are described in more detail below.

Recombinant DNA Techniques

Methods for producing and screening for specific antibodies usingrecombinant DNA technology are routine and well known in the art (e.g.U.S. Pat. No. 4,816,567). DNA encoding the monoclonal antibodies may bereadily isolated and/or sequenced using conventional procedures (e.g.,by using oligonucleotide probes that are capable of binding specificallyto genes encoding the heavy and light chains of murine antibodies). Onceisolated, the DNA may be placed into expression vectors, which are thentransfected into host cells such as E. coli cells, simian COS cells,Chinese Hamster Ovary (CHO) cells, or myeloma cells that do nototherwise produce antibody protein, to obtain the synthesis ofmonoclonal antibodies in the recombinant host cells. Review articles onrecombinant expression in bacteria of DNA encoding the antibody includeSkerra et al. (1993) Curr. Opinion in Immunol. 5:256-262 and Pluckthun(1992) Immunol. Revs. 130:151-188. As described below, for antibodiesgenerated by phage display and humanization of antibodies, DNA orgenetic material for recombinant antibodies can be obtained fromsource(s) other than hybridomas to generate antibodies of the invention.

Recombinant expression of an antibody or variant thereof generallyrequires construction of an expression vector containing apolynucleotide that encodes the antibody. The invention, thus, providesreplicable vectors that include a nucleotide sequence encoding anantibody molecule, a heavy or light chain of an antibody, a heavy orlight chain variable domain of an antibody or a portion thereof, or aheavy or light chain CDR, operably linked to a promoter. Such vectorsmay include the nucleotide sequence encoding the constant region of theantibody molecule (see, e.g., U.S. Pat. Nos. 5,981,216; 5,591,639;5,658,759 and 5,122,464) and the variable domain of the antibody may becloned into such a vector for expression of the entire heavy, the entirelight chain, or both the entire heavy and light chains.

Once the expression vector is transferred to a host cell by conventionaltechniques, the transfected cells are then cultured by conventionaltechniques to produce an antibody. Thus, the invention includes hostcells containing a polynucleotide encoding an antibody of the inventionor fragments thereof, or a heavy or light chain thereof, or portionthereof, or a single-chain antibody of the invention, operably linked toa heterologous promoter. In certain embodiments for the expression ofdouble-chained antibodies, vectors encoding both the heavy and lightchains may be co-expressed in the host cell for expression of the entireimmunoglobulin molecule, as detailed below.

Mammalian cell lines available as hosts for expression of recombinantantibodies are well known in the art and include many immortalized celllines available from the American Type Culture Collection (ATCC),including but not limited to Chinese hamster ovary (CHO) cells, HeLacells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), humanhepatocellular carcinoma cells (e.g., Hep G2), human epithelial kidney293 cells, and a number of other cell lines. Different host cells havecharacteristic and specific mechanisms for the post-translationalprocessing and modification of proteins and gene products. Appropriatecell lines or host systems can be chosen to ensure the correctmodification and processing of the antibody or portion thereofexpressed. To this end, eukaryotic host cells which possess the cellularmachinery for proper processing of the primary transcript,glycosylation, and phosphorylation of the gene product may be used. Suchmammalian host cells include but are not limited to CHO, VERY, BHK,Hela, COS, MDCK, 293, 3T3, W138, BT483, Hs578T, HTB2, BT2O and T47D, NS0(a murine myeloma cell line that does not endogenously produce anyfunctional immunoglobulin chains), SP20, CRL7O3O and HsS78Bst cells.Human cell lines developed by immortalizing human lymphocytes can beused to recombinantly produce monoclonal antibodies. The human cell linePER.C6®. (Crucell, Netherlands) can be used to recombinantly producemonoclonal antibodies.

Additional cell lines which may be used as hosts for expression ofrecombinant antibodies include, but are not limited to, insect cells(e.g. Sf21/Sf9, Trichoplusia ni Bti-Tn5b1-4) or yeast cells (e.g. S.cerevisiae, Pichia, U.S. Pat. No. 7,326,681; etc.), plants cells(US20080066200); and chicken cells (WO2008142124).

In certain embodiments, antibodies of the invention are expressed in acell line with stable expression of the antibody. Stable expression canbe used for long-term, high-yield production of recombinant proteins.For example, cell lines which stably express the antibody molecule maybe generated. Host cells can be transformed with an appropriatelyengineered vector that include expression control elements (e.g.,promoter, enhancer, transcription terminators, polyadenylation sites,etc.), and a selectable marker gene. Following the introduction of theforeign DNA, cells may be allowed to grow for 1-2 days in an enrichedmedia, and then are switched to a selective media. The selectable markerin the recombinant plasmid confers resistance to the selection andallows cells that stably integrated the plasmid into their chromosomesto grow and form foci which in turn can be cloned and expanded into celllines. Methods for producing stable cell lines with a high yield arewell known in the art and reagents are generally available commercially.

In certain embodiments, antibodies of the invention are expressed in acell line with transient expression of the antibody. Transienttransfection is a process in which the nucleic acid introduced into acell does not integrate into the genome or chromosomal DNA of that cell.It is in fact maintained as an extra-chromosomal element, e.g. as anepisome, in the cell. Transcription processes of the nucleic acid of theepisome are not affected and a protein encoded by the nucleic acid ofthe episome is produced.

The cell line, either stable or transiently transfected, is maintainedin cell culture medium and conditions well known in the art resulting inthe expression and production of monoclonal antibodies. In certainembodiments, the mammalian cell culture media is based on commerciallyavailable media formulations, including, for example, DMEM or Ham's F12.In other embodiments, the cell culture media is modified to supportincreases in both cell growth and biologic protein expression. As usedherein, the terms “cell culture medium,” “culture medium,” and “mediumformulation” refer to a nutritive solution for the maintenance, growth,propagation, or expansion of cells in an artificial in vitro environmentoutside of a multicellular organism or tissue. Cell culture medium maybe optimized for a specific cell culture use, including, for example,cell culture growth medium which is formulated to promote cellulargrowth, or cell culture production medium which is formulated to promoterecombinant protein production. The terms nutrient, ingredient, andcomponent are used interchangeably herein to refer to the constituentsthat make up a cell culture medium.

In one embodiment, the cell lines are maintained using a fed batchmethod. As used herein, “fed batch method,” refers to a method by whicha cell culture is supplied with additional nutrients after first beingincubated with a basal medium. For example, a fed batch method mayinclude adding supplemental media according to a determined feedingschedule within a given time period. Thus, a “fed batch cell culture”refers to a cell culture wherein the cells, typically mammalian, andculture medium are supplied to the culturing vessel initially andadditional culture nutrients are fed, continuously or in discreteincrements, to the culture during culturing, with or without periodiccell and/or product harvest before termination of culture.

The cell culture medium used and the nutrients contained therein areknown to one of skill in the art. In one embodiment, the cell culturemedium includes a basal medium and at least one hydrolysate, e.g.,soy-based hydrolysate, a yeast-based hydrolysate, or a combination ofthe two types of hydrolysates resulting in a modified basal medium. Inanother embodiment, the additional nutrients may include only a basalmedium, such as a concentrated basal medium, or may include onlyhydrolysates, or concentrated hydrolysates. Suitable basal mediainclude, but are not limited to Dulbecco's Modified Eagle's Medium(DMEM), DME/F12, Minimal Essential Medium (MEM), Basal Medium Eagle(BME), RPMI 1640, F-10, F-12, α-Minimal Essential Medium (α-MEM),Glasgow's Minimal Essential Medium (G-MEM), PF CHO (see, e.g., CHOprotein free medium (Sigma) or EX-CELL™ 325 PF CHO Serum-Free Medium forCHO Cells Protein-Free (SAFC Bioscience), and Iscove's ModifiedDulbecco's Medium. Other examples of basal media which may be used inthe invention include BME Basal Medium (Gibco-Invitrogen; see alsoEagle, H (1965) Proc. Soc. Exp. Biol. Med. 89, 36); Dulbecco's ModifiedEagle Medium (DMEM, powder) (Gibco-Invitrogen (#31600); see alsoDulbecco and Freeman (1959) Virology. 8:396; Smith et al. (1960)Virology. 12:185. Tissue Culture Standards Committee, In Vitro 6:2, 93);CMRL 1066 Medium (Gibco-Invitrogen (#11530); see also Parker et al.(1957) Special Publications, N.Y. Academy of Sciences, 5:303).

The basal medium may be serum-free, meaning that the medium contains noserum (e.g., fetal bovine serum (FBS), horse serum, goat serum, or anyother animal-derived serum known to one skilled in the art) or animalprotein free media or chemically defined media.

The basal medium may be modified in order to remove certainnon-nutritional components found in standard basal medium, such asvarious inorganic and organic buffers, surfactant(s), and sodiumchloride. Removing such components from basal cell medium allows anincreased concentration of the remaining nutritional components, and mayimprove overall cell growth and protein expression. In addition, omittedcomponents may be added back into the cell culture medium containing themodified basal cell medium according to the requirements of the cellculture conditions. In certain embodiments, the cell culture mediumcontains a modified basal cell medium, and at least one of the followingnutrients, an iron source, a recombinant growth factor; a buffer; asurfactant; an osmolarity regulator; an energy source; and non-animalhydrolysates. In addition, the modified basal cell medium may optionallycontain amino acids, vitamins, or a combination of both amino acids andvitamins. In another embodiment, the modified basal medium furthercontains glutamine, e.g, L-glutamine, and/or methotrexate.

Antibody production can be conducted in large quantity by a bioreactorprocess using fed-batch, batch, perfusion or continuous feed bioreactormethods known in the art. Large-scale bioreactors have at least 1000liters of capacity, in one embodiment about 1,000 to 100,000 liters ofcapacity. These bioreactors may use agitator impellers to distributeoxygen and nutrients. Small scale bioreactors refers generally to cellculturing in no more than approximately 100 liters in volumetriccapacity, and can range from about 1 liter to about 100 liters.Alternatively, single-use bioreactors (SUB) may be used for eitherlarge-scale or small-scale culturing.

Temperature, pH, agitation, aeration and inoculum density will varydepending upon the host cells used and the recombinant protein to beexpressed. For example, a recombinant protein cell culture may bemaintained at a temperature between 30° C. and 45° C. The pH of theculture medium may be monitored during the culture process such that thepH stays at an optimum level, which may be for certain host cells,within a pH range of 6.0 to 8.0. An impeller driven mixing may be usedfor such culture methods for agitation. The rotational speed of theimpeller may be approximately 50 to 200 cm/sec tip speed, but otherairlift or other mixing/aeration systems known in the art may be used,depending on the type of host cell being cultured. Sufficient aerationis provided to maintain a dissolved oxygen concentration ofapproximately 20% to 80% air saturation in the culture, again, dependingupon the selected host cell being cultured. Alternatively, a bioreactormay sparge air or oxygen directly into the culture medium. Other methodsof oxygen supply exist, including bubble-free aeration systems employinghollow fiber membrane aerators.

Phage Display Techniques

Monoclonal antibodies or antibody fragments can be isolated fromantibody phage libraries generated using the techniques described inMcCafferty et al. (1990) Nature. 348:552-554; Clackson et al. (1991)Nature. 352:624-628 and Marks et al. (1991) J. Mol. Biol. 222:581-597.In such methods antibodies can be isolated by screening a recombinantcombinatorial antibody library. In one embodiment a scFv phage displaylibrary, prepared using human VL and VH cDNAs prepared from mRNA derivedfrom human lymphocytes. Methodologies for preparing and screening suchlibraries are known in the art.

In addition to commercially available kits for generating phage displaylibraries (e.g., the Pharmacia Recombinant Phage Antibody System,catalog no. 27-9400-01; and the Stratagene SurfZAP™ phage display kit,catalog no. 240612), examples of methods and reagents particularlyamenable for use in generating and screening antibody display librariescan be found in, for example, U.S. Pat. Nos. 6,248,516; 6,545,142;6,291,158; 6,291,159; 6,291,160; 6,291,161; 6,680,192; 5,969,108;6,172,197; 6,806,079; 5,885,793; 6,521,404; 6,544,731; 6,555,313;6,593,081; 6,582,915; 7,195,866. Thus, these techniques are viablealternatives to traditional monoclonal antibody hybridoma techniques forgeneration and isolation of monoclonal antibodies.

In phage display methods, functional antibody domains are displayed onthe surface of phage particles which carry the polynucleotide sequencesencoding them. In a particular embodiment, such phage can be utilized todisplay antigen-binding domains expressed from a repertoire orcombinatorial antibody library (e.g., human or murine). Phage expressingan antigen binding domain that binds the antigen of interest can beselected or identified with antigen, e.g., using labeled antigen orantigen bound or captured to a solid surface or bead. Phage used inthese methods are typically filamentous phage including fd and M13binding domains expressed from phage with Fab, Fv or disulfidestabilized Fv antibody domains recombinantly fused to either the phagegene III or gene VIII protein.

As described in the above references, after phage selection, theantibody coding regions from the phage can be isolated and used togenerate whole antibodies, including human antibodies, humanizedantibodies, or any other desired antigen binding fragment, and expressedin any desired host, including mammalian cells, insect cells, plantcells, yeast, and bacteria, e.g., as described in detail below. Forexample, techniques to recombinantly produce Fab, Fab′ and F(ab′)2fragments can also be employed using methods known in the art such asthose disclosed in PCT publication WO 92/22324; Mullinax et al. (1992)BioTechniques. 12(6):864-869; and Better et al. (1988) Science.240:1041-1043.

Examples of techniques which can be used to produce single-chain Fvs andantibodies include those described in U.S. Pat. Nos. 4,946,778 and5,258,498. Thus, techniques described above and those well known in theart can be used to generate recombinant antibodies wherein the bindingdomain, e.g. ScFv, was isolated from a phage display library.

Antibody Purification and Isolation

Once an antibody molecule has been produced by recombinant or hybridomaexpression, it may be purified by any method known in the art forpurification of an immunoglobulin molecule, for example, bychromatography (e.g., ion exchange, affinity, particularly by affinityfor the specific antigens Protein A or Protein G, and sizing columnchromatography), centrifugation, differential solubility, or by anyother standard technique for the purification of proteins. Further, theantibodies of the present invention or fragments thereof may be fused toheterologous polypeptide sequences (referred to herein as “tags”) tofacilitate purification.

When using recombinant techniques, the antibody can be producedintracellularly, in the periplasmic space, or directly secreted into themedium. If the antibody is produced intracellularly, as a first step,the particulate debris, either host cells or lysed fragments, isremoved, for example, by centrifugation or ultrafiltration. Carter etal. (1992) Bio/Technology. 10:163-167 describe a procedure for isolatingantibodies which are secreted into the periplasmic space of E. coli.Where the antibody is secreted into the medium, supernatants from suchexpression systems are generally first concentrated using a commerciallyavailable protein concentration filter, for example, an Amicon orMillipore Pellicon ultrafiltration unit. A protease inhibitor such asPMSF may be included in any of the foregoing steps to inhibitproteolysis and antibiotics may be included to prevent the growth ofadventitious contaminants.

The antibody composition prepared from the cells can be purified using,for example, hydroxylapatite chromatography, hydrophobic interactionchromatography, ion exchange chromatography, gel electrophoresis,dialysis, and/or affinity chromatography either alone or in combinationwith other purification steps. The suitability of protein A as anaffinity ligand depends on the species and isotype of any immunoglobulinFc domain that is present in the antibody and will be understood by oneof skill in the art. The matrix to which the affinity ligand is attachedis most often agarose, but other matrices are available. Mechanicallystable matrices such as controlled pore glass orpoly(styrenedivinyl)benzene allow for faster flow rates and shorterprocessing times than can be achieved with agarose. Where the antibodyincludes a CH₃ domain, the Bakerbond ABX resin (J.T. Baker,Phillipsburg, N.J.) is useful for purification. Other techniques forprotein purification such as fractionation on an ion-exchange column,ethanol precipitation, Reverse Phase HPLC, chromatography on silica,chromatography on heparin, SEPHAROSE chromatography on an anion orcation exchange resin (such as a polyaspartic acid column),chromatofocusing, SDS-PAGE, and ammonium sulfate precipitation are alsoavailable depending on the antibody to be recovered.

Following any preliminary purification step(s), the mixture thatincludes the antibody of interest and contaminants may be subjected tolow pH hydrophobic interaction chromatography using an elution buffer ata pH between about 2.5-4.5, and performed at low salt concentrations(e.g., from about 0-0.25 M salt).

Thus, in certain embodiments is provided antibodies of the inventionthat are substantially purified/isolated. In one embodiment, theseisolated/purified recombinantly expressed antibodies may be administeredto a patient to mediate a prophylactic or therapeutic effect. Aprophylactic is a medication or a treatment designed and used to preventa disease, disorder or infection from occurring. A therapeutic isconcerned specifically with the treatment of a particular disease,disorder or infection. A therapeutic dose is the amount needed to treata particular disease, disorder or infection. In another embodiment theseisolated/purified antibodies may be used to diagnose influenza virusinfection, for example, influenza B virus infection, or, in otherembodiments, influenza A and influenza B virus infection.

Human Antibodies

Human antibodies can be generated using methods well known in the art.Human antibodies avoid some of the problems associated with antibodiesthat possess murine or rat variable and/or constant regions. Thepresence of such murine or rat derived proteins can lead to the rapidclearance of the antibodies or can lead to the generation of an immuneresponse against the antibody by a patient.

Human antibodies can be derived by in vitro methods. Suitable examplesinclude but are not limited to phage display (MedImmune (formerly CAT),Morphosys, Dyax, Biosite/Medarex, Xoma, Symphogen, Alexion (formerlyProliferon), Affimed) ribosome display (Medlmmune (formerly CAT)), yeastdisplay, and the like. The phage display technology (See e.g., U.S. Pat.No. 5,969,108) can be used to produce human antibodies and antibodyfragments in vitro, from immunoglobulin variable (V) domain generepertoires from unimmunized donors. According to this technique,antibody V domain genes are cloned in-frame into either a major or minorcoat protein gene of a filamentous bacteriophage, such as M13 or fd, anddisplayed as functional antibody fragments on the surface of the phageparticle. Because the filamentous particle contains a single-strandedDNA copy of the phage genome, selections based on the functionalproperties of the antibody also result in selection of the gene encodingthe antibody exhibiting those properties. Thus, the phage mimics some ofthe properties of the B-cell. Phage display can be performed in avariety of formats, reviewed in, e.g., Johnson and Chiswell (1993)Current Opinion in Structural Biology. 3:564-571. Several sources ofV-gene segments can be used for phage display. Clackson et al. (1991)Nature. 352:624-628 (1991) isolated a diverse array of anti-oxazoloneantibodies from a small random combinatorial library of V genes derivedfrom the spleens of immunized mice. A repertoire of V genes fromunimmunized human donors can be constructed and antibodies to a diversearray of antigens (including self-antigens) can be isolated essentiallyfollowing the techniques described by Marks et al. (1991) J. Mol. Biol.222:581-597, or Griffith et al. (1993) EMBO J. 12:725-734. See, also,U.S. Pat. Nos. 5,565,332 and 5,573,905.

As discussed above, human antibodies may also be generated by in vitroactivated B cells (see U.S. Pat. Nos. 5,567,610 and 5,229,275).

Immunoglobulin genes undergo various modifications during maturation ofthe immune response, including recombination between V, D and J genesegments, isotype switching, and hypermutation in the variable regions.Recombination and somatic hypermutation are the foundation forgeneration of antibody diversity and affinity maturation, but they canalso generate sequence liabilities that may make commercial productionof such immunoglobulins as therapeutic agents difficult or increase theimmunogenicity risk of the antibody. In general, mutations in CDRregions are likely to contribute to improved affinity and function,while mutations in framework regions may increase the risk ofimmunogenicity. This risk can be reduced by reverting frameworkmutations to germline while ensuring that activity of the antibody isnot adversely impacted. The diversification processes may also generatesome structural liabilities or these structural liabilities may existwithin germline sequences contributing to the heavy and light chainvariable domains. Regardless of the source, it may be desirable toremove potential structural liabilities that may result in instability,aggregation, heterogeneity of product, or increased immunogenicity.Examples of undesirable liabilities include unpaired cysteines (whichmay lead to disulfide bond scrambling, or variable sulfhydryl adductformation), N-linked glycosylation sites (resulting in heterogeneity ofstructure and activity), as well as deamidation (e.g. NG, NS),isomerization (DG), oxidation (exposed methionine), and hydrolysis (DP)sites.

Accordingly, in order to reduce the risk of immunogenicity and improvepharmaceutical properties, it may be desirable to revert a frameworksequence to germline, revert a CDR to germline, and/or remove astructural liability.

Thus, in one embodiment, where a particular antibody differs from itsrespective germline sequence at the amino acid level, the antibodysequence can be mutated back to the germline sequence. Such correctivemutations can occur at one, two, three or more positions, or acombination of any of the mutated positions, using standard molecularbiological techniques.

Antibody Fragments

In certain embodiments, the present antibodies are antibody fragments orantibodies that include these fragments. The antibody fragment includesa portion of the full length antibody, which generally is the antigenbinding or variable region thereof. Examples of antibody fragmentsinclude Fab, Fab′, F(ab′)₂, Fd and Fv fragments, diabodies; linearantibodies (U.S. Pat. No. 5,641,870) and single-chain antibodymolecules.

Traditionally, these fragments were derived via proteolytic digestion ofintact antibodies using techniques well known in the art. However, thesefragments can now be produced directly by recombinant host cells. Fab,Fv and scFv antibody fragments can all be expressed in and secreted fromE. coli, thus allowing the facile production of large amounts of thesefragments. In one embodiment, the antibody fragments can be isolatedfrom the antibody phage libraries discussed above. Alternatively,Fab′-SH fragments can also be directly recovered from E. coli andchemically coupled to form F(ab′)₂ fragments (Carter et al. (1992)Bio/Technology. 10:163-167). According to another approach, F(ab′)₂fragments can be isolated directly from recombinant host cell culture.Other techniques for the production of antibody fragments will beapparent to the skilled practitioner. In other embodiments, the antibodyof choice is a single-chain Fv fragment (scFv). In certain embodiments,the antibody is not a Fab fragment. Fv and scFv are the only specieswith intact combining sites that are devoid of constant regions; thus,they are suitable for reduced nonspecific binding during in vivo use.scFv fusion proteins may be constructed to yield fusion of an effectorprotein at either the amino or the carboxy terminus of an scFv.

In certain embodiments, the present antibodies are domain antibodies,e.g., antibodies containing the small functional binding units ofantibodies, corresponding to the variable regions of the heavy (VH) orlight (VL) chains of human antibodies. Examples of domain antibodiesinclude, but are not limited to, those of Domantis (see, for example,WO04/058821; WO04/081026; WO04/003019; WO03/002609; U.S. Pat. Nos.6,291,158; 6,582,915; 6,696,245; and 6,593,081).

In certain embodiments of the invention, the present antibodies arelinear antibodies. Linear antibodies include a pair of tandem Fdsegments (VH-CH1-VH-CH1) which form a pair of antigen-binding regions.See, Zapata et al. (1995) Protein Eng. 8(10):1057-1062.

Other Amino Acid Sequence Modifications

In addition to the above described human, humanized and/or chimericantibodies, the present invention also encompasses further modificationsand, their variants and fragments thereof, of the antibodies of theinvention including one or more amino acid residues and/or polypeptidesubstitutions, additions and/or deletions in the variable light (VL)domain and/or variable heavy (VH) domain and/or Fc region and posttranslational modifications. Included in these modifications areantibody conjugates wherein an antibody has been covalently attached toa moiety. Moieties suitable for attachment to the antibodies include butare not limited to, proteins, peptides, drugs, labels, and cytotoxins.These changes to the antibodies may be made to alter or fine tune thecharacteristics (biochemical, binding and/or functional) of theantibodies as is appropriate for treatment and/or diagnosis of influenzavirus infection. Methods for forming conjugates, making amino acidand/or polypeptide changes and post-translational modifications are wellknown in the art, some of which are detailed below.

Amino acid changes to the antibodies necessarily results in sequencesthat are less than 100% identical to the above identified antibodysequences or parent antibody sequence. In certain embodiments, in thiscontext, the antibodies many have about 25% to about 95% sequenceidentity to the amino acid sequence of either the heavy or light chainvariable domain of an antibody as described herein. Thus, in oneembodiment a modified antibody may have an amino acid sequence having atleast 25%, 35%, 45%, 55%, 65%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or99% amino acid sequence identity or similarity with the amino acidsequence of either the heavy or light chain variable domain of anantibody as described herein. In another embodiment, an altered antibodymay have an amino acid sequence having at least 25%, 35%, 45%, 55%, 65%,75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% amino acid sequenceidentity or similarity with the amino acid sequence of the heavy orlight chain CDR-1, CDR-2, or CDR-3 of an antibody as described herein.In another embodiment, an altered antibody may have an amino acidsequence having at least 25%, 35%, 45%, 55%, 65%, 75%, 80%, 85%, 90%,95%, 96%, 97%, 98% or 99% amino acid sequence identity or similaritywith the amino acid sequence of the heavy or light chain FR1, FR2, FR3or FR4 of an antibody as described herein.

In certain embodiments, altered antibodies are generated by one or moreamino acid alterations (e.g., substitutions, deletion and/or additions)introduced in one or more of the variable regions of the antibody. Inanother embodiment, the amino acid alterations are introduced in theframework regions. One or more alterations of framework region residuesmay result in an improvement in the binding affinity of the antibody forthe antigen. This may be especially true when these changes are made tohumanized antibodies wherein the framework region may be from adifferent species than the CDR regions. Examples of framework regionresidues to modify include those which non-covalently bind antigendirectly (Amit et al. (1986) Science. 233:747-753); interact with/effectthe conformation of a CDR (Chothia et al. (1987) J. Mol. Biol.196:901-917); and/or participate in the VL-VH interface (U.S. Pat. Nos.5,225,539 and 6,548,640). In one embodiment, from about one to aboutfive framework residues may be altered. Sometimes, this may besufficient to yield an antibody mutant suitable for use in preclinicaltrials, even where none of the hypervariable region residues have beenaltered. Normally, however, an altered antibody will include additionalhypervariable region alteration(s).

One useful procedure for generating altered antibodies is called“alanine scanning mutagenesis” (Cunningham and Wells (1989) Science.244:1081-1085). In this method, one or more of the hypervariable regionresidue(s) are replaced by alanine or polyalanine residue(s) to alterthe interaction of the amino acids with the target antigen. Thosehypervariable region residue(s) demonstrating functional sensitivity tothe substitutions then are refined by introducing additional or othermutations at or for the sites of substitution. Thus, while the site forintroducing an amino acid sequence variation is predetermined, thenature of the mutation per se need not be predetermined. The Ala-mutantsproduced this way are screened for their biological activity asdescribed herein.

In certain embodiments the substitutional variant involves substitutingone or more hypervariable region residues of a parent antibody (e.g. ahumanized or human antibody). Generally, the resulting variant(s)selected for further development will have improved biologicalproperties relative to the parent antibody from which they aregenerated. A convenient way for generating such substitutional variantsinvolves affinity maturation using phage display (Hawkins et al. (1992)J. Mol. Biol. 254:889-896 and Lowman et al. (1991) Biochemistry.30(45):10832-10837)). Briefly, several hypervariable region sites (e.g.,6-7 sites) are mutated to generate all possible amino acid substitutionsat each site. The antibody mutants thus generated are displayed in amonovalent fashion from filamentous phage particles as fusions to thegene III product of M13 packaged within each particle. Thephage-displayed mutants are then screened for their biological activity(e.g., binding affinity) as herein disclosed.

Mutations in antibody sequences may include substitutions, deletions,including internal deletions, additions, including additions yieldingfusion proteins, or conservative substitutions of amino acid residueswithin and/or adjacent to the amino acid sequence, but that result in a“silent” change, in that the change produces a functionally-equivalentantibody. Conservative amino acid substitutions may be made on the basisof similarity in polarity, charge, solubility, hydrophobicity,hydrophilicity, and/or the amphipathic nature of the residues involved.For example, non-polar (hydrophobic) amino acids include alanine,leucine, isoleucine, valine, proline, phenylalanine, tryptophan, andmethionine; polar neutral amino acids include glycine, serine,threonine, cysteine, tyrosine, asparagine, and glutamine; positivelycharged (basic) amino acids include arginine, lysine, and histidine; andnegatively charged (acidic) amino acids include aspartic acid andglutamic acid. In addition, glycine and proline are residues that caninfluence chain orientation. Non-conservative substitutions will entailexchanging a member of one of these classes for a member of anotherclass. Furthermore, if desired, non-classical amino acids or chemicalamino acid analogs can be introduced as a substitution or addition intothe antibody sequence. Non-classical amino acids include, but are notlimited to, the D-isomers of the common amino acids, α-amino isobutyricacid, 4-aminobutyric acid, Abu, 2-amino butyric acid, γ-Abu, ε-Ahx,6-amino hexanoic acid, Aib, 2-amino isobutyric acid, 3-amino propionicacid, ornithine, norleucine, norvaline, hydroxyproline, sarcosine,citrulline, cysteic acid, t-butylglycine, t-butylalanine, phenylglycine,cyclohexylalanine, β-alanine, fluoro-amino acids, designer amino acidssuch as β-methyl amino acids, Cα-methyl amino acids, Nα-methyl aminoacids, and amino acid analogs in general.

In another embodiment, any cysteine residue not involved in maintainingthe proper conformation of the antibody also may be substituted,generally with serine, to improve the oxidative stability of themolecule and prevent aberrant crosslinking. Conversely, cysteine bond(s)may be added to the antibody to improve its stability (particularlywhere the antibody is an antibody fragment such as an Fv fragment).

Variant Fc Regions

It is known that variants of the Fc region (e.g., amino acidsubstitutions and/or additions and/or deletions) enhance or diminisheffector function of the antibody (See e.g., U.S. Pat. Nos. 5,624,821;5,885,573; 6,538,124; 7,317,091; 5,648,260; 6,538,124; WO 03/074679; WO04/029207; WO 04/099249; WO 99/58572; US Publication No. 2006/0134105;2004/0132101; 2006/0008883) and may alter the pharmacokinetic properties(e.g. half-life) of the antibody (see, U.S. Pat. Nos. 6,277,375 and7,083,784). Thus, in certain embodiments, the antibodies of theinvention include an altered Fc region (also referred to herein as“variant Fc region”) in which one or more alterations have been made inthe Fc region in order to change functional and/or pharmacokineticproperties of the antibodies. Such alterations may result in a decreaseor increase of Clq binding and complement dependent cytotoxicity (CDC)or of FcγR binding, for IgG, and antibody-dependent cellularcytotoxicity (ADCC), or antibody dependent cell-mediated phagocytosis(ADCP). The present invention encompasses the antibodies describedherein with variant Fc regions wherein changes have been made to finetune the effector function, enhancing or diminishing, providing adesired effector function. Accordingly, the antibodies of the inventioninclude a variant Fc region (i.e., Fc regions that have been altered asdiscussed below). Antibodies of the invention having a variant Fc regionare also referred to here as “Fc variant antibodies.” As used hereinnative refers to the unmodified parental sequence and the antibody witha native Fc region is herein referred to as a “native Fc antibody”. Fcvariant antibodies can be generated by numerous methods well known toone skilled in the art. Non-limiting examples include, isolatingantibody coding regions (e.g., from hybridoma) and making one or moredesired substitutions in the Fc region of the isolated antibody codingregion. Alternatively, the antigen-binding portion (e.g., variableregions) of an antibody may be sub-cloned into a vector encoding avariant Fc region. In one embodiment, the variant Fc region exhibits asimilar level of inducing effector function as compared to the native Fcregion. In another embodiment, the variant Fc region exhibits a higherinduction of effector function as compared to the native Fc. Somespecific embodiments of variant Fc regions are detailed infra. Methodsfor measuring effector function are well known in the art.

The effector function of an antibody is modified through changes in theFc region, including but not limited to, amino acid substitutions, aminoacid additions, amino acid deletions and changes in post-translationalmodifications to Fc amino acids (e.g. glycosylation). The methodsdescribed below may be used to fine tune the effector function of apresent antibody, a ratio of the binding properties of the Fc region forthe FcR (e.g., affinity and specificity), resulting in a therapeuticantibody with the desired properties.

It is understood that the Fc region, as used herein, includes thepolypeptides that make up the constant region of an antibody excludingthe first constant region immunoglobulin domain. Thus, Fc refers to thelast two constant region immunoglobulin domains of IgA, IgD, and IgG,and the last three constant region immunoglobulin domains of IgE andIgM, and the flexible hinge N-terminal to these domains. For IgA and IgMFc may include the J chain. For IgG, Fc includes immunoglobulin domainsCgamma2 and Cgamma3 (Cγ2 and Cγ3) and the hinge between Cgamma1 (Cγ1)and Cgamma2 (Cγ2).

Although the boundaries of the Fc region may vary, the human IgG heavychain Fc region is can be defined to include residues C226 or P230 toits carboxyl-terminus, wherein the numbering is according to the EUindex as set forth in Kabat. Fc may refer to this region in isolation,or this region in the context of an antibody, antibody fragment, or Fcfusion protein. Polymorphisms have been observed at a number ofdifferent Fc positions, including but not limited to positions 270, 272,312, 315, 356, and 358 as numbered by the EU index, and thus slightdifferences between the presented sequence and sequences in the priorart may exist.

In one embodiment, Fc variant antibodies exhibit altered bindingaffinity for one or more Fc receptors including, but not limited toFcRn, FcγRI (CD64) including isoforms FcγRIA, FcγRIB, and FcγRIC; FcγRII(CD32 including isoforms FcγRIIA, FcγRIIB, and FcγRIIC); and FcγRIII(CD16, including isoforms FcγRIIIA and FcγRIIIB) as compared to annative Fc antibody.

In one embodiment, an Fc variant antibody has enhanced binding to one ormore Fc ligand relative to a native Fc antibody. In another embodiment,the Fc variant antibody exhibits increased or decreased affinity for anFc ligand that is at least 2 fold, or at least 3 fold, or at least 5fold, or at least 7 fold, or at least 10 fold, or at least 20 fold, orat least 30 fold, or at least 40 fold, or at least 50 fold, or at least60 fold, or at least 70 fold, or at least 80 fold, or at least 90 fold,or at least 100 fold, and up to 25 fold, or up to 50 fold, or up to 75fold, or up to 100 fold, or up to 200 fold, or is between 2 fold and 10fold, or between 5 fold and 50 fold, or between 25 fold and 100 fold, orbetween 75 fold and 200 fold, or between 100 and 200 fold, more or lessthan a native Fc antibody. In another embodiment, Fc variant antibodiesexhibit affinities for an Fc ligand that are at least 90%, at least 80%,at least 70%, at least 60%, at least 50%, at least 40%, at least 30%, atleast 20%, at least 10%, or at least 5% more or less than an native Fcantibody. In certain embodiments, an Fc variant antibody has increasedaffinity for an Fc ligand. In other embodiments, an Fc variant antibodyhas decreased affinity for an Fc ligand.

In a specific embodiment, an Fc variant antibody has enhanced binding tothe Fc receptor FcγRIIIA. In another specific embodiment, an Fc variantantibody has enhanced binding to the Fc receptor FcγRIIB. In a furtherspecific embodiment, an Fc variant antibody has enhanced binding to boththe Fc receptors FcγRIIIA and FcγRIIB. In certain embodiments, Fcvariant antibodies that have enhanced binding to FcγRIIIA do not have aconcomitant increase in binding the FcγRIIB receptor as compared to anative Fc antibody. In a specific embodiment, an Fc variant antibody hasreduced binding to the Fc receptor FcγRIIIA. In a further specificembodiment, an Fc variant antibody has reduced binding to the Fcreceptor FcγRIIB. In still another specific embodiment, an Fc variantantibody exhibiting altered affinity for FcγRIIIA and/or FcγRIIB hasenhanced binding to the Fc receptor FcRn. In yet another specificembodiment, an Fc variant antibody exhibiting altered affinity forFcγRIIIA and/or FcγRIIB has altered binding to C1q relative to a nativeFc antibody.

In one embodiment, Fc variant antibodies exhibit affinities for FcγRIIIAreceptor that are at least 2 fold, or at least 3 fold, or at least 5fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or atleast 30 fold, or at least 40 fold, or at least 50 fold, or at least 60fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, orat least 100 fold, or up to 50 fold, or up to 60 fold, or up to 70 fold,or up to 80 fold, or up to 90 fold, or up to 100 fold, or up to 200fold, or are between 2 fold and 10 fold, or between 5 fold and 50 fold,or between 25 fold and 100 fold, or between 75 fold and 200 fold, orbetween 100 and 200 fold, more or less than an native Fc antibody. Inanother embodiment, Fc variant antibodies exhibit affinities forFcγRIIIA that are at least 90%, at least 80%, at least 70%, at least60%, at least 50%, at least 40%, at least 30%, at least 20%, at least10%, or at least 5% more or less than an native Fc antibody.

In one embodiment, Fc variant antibodies exhibit affinities for FcγRIIBreceptor that are at least 2 fold, or at least 3 fold, or at least 5fold, or at least 7 fold, or a least 10 fold, or at least 20 fold, or atleast 30 fold, or at least 40 fold, or at least 50 fold, or at least 60fold, or at least 70 fold, or at least 80 fold, or at least 90 fold, orat least 100 fold, or up to 50 fold, or up to 60 fold, or up to 70 fold,or up to 80 fold, or up to 90 fold, or up to 100 fold, or up to 200fold, or are between 2 fold and 10 fold, or between 5 fold and 50 fold,or between 25 fold and 100 fold, or between 75 fold and 200 fold, orbetween 100 and 200 fold, more or less than an native Fc antibody. Inanother embodiment, Fc variant antibodies exhibit affinities for FcγRIIBthat are at least 90%, at least 80%, at least 70%, at least 60%, atleast 50%, at least 40%, at least 30%, at least 20%, at least 10%, or atleast 5% more or less than an native Fc antibody.

In one embodiment, Fc variant antibodies exhibit increased or decreasedaffinities to C1q relative to a native Fc antibody. In anotherembodiment, Fc variant antibodies exhibit affinities for C1q receptorthat are at least 2 fold, or at least 3 fold, or at least 5 fold, or atleast 7 fold, or at least 10 fold, or at least 20 fold, or at least 30fold, or at least 40 fold, or at least 50 fold, or at least 60 fold, orat least 70 fold, or at least 80 fold, or at least 90 fold, or at least100 fold, or up to 50 fold, or up to 60 fold, or up to 70 fold, or up to80 fold, or up to 90 fold, or up to 100 fold, or up to 200 fold, or arebetween 2 fold and 10 fold, or between 5 fold and 50 fold, or between 25fold and 100 fold, or between 75 fold and 200 fold, or between 100 and200 fold, more or less than an native Fc antibody. In anotherembodiment, Fc variant antibodies exhibit affinities for C1q that are atleast 90%, at least 80%, at least 70%, at least 60%, at least 50%, atleast 40%, at least 30%, at least 20%, at least 10%, or at least 5% moreor less than an native Fc antibody. In still another specificembodiment, an Fc variant antibody exhibiting altered affinity for Ciqhas enhanced binding to the Fc receptor FcRn. In yet another specificembodiment, an Fc variant antibody exhibiting altered affinity for C1qhas altered binding to FcγRIIIA and/or FcγRIIB relative to a native Fcantibody.

It is well known in the art that antibodies are capable of directing theattack and destruction through multiple processes collectively known inthe art as antibody effector functions. One of these processes, known as“antibody-dependent cell-mediated cytotoxicity” or “ADCC” refers to aform of cytotoxicity in which secreted Ig bound onto Fc receptors (FcRs)present on certain cytotoxic cells (e.g., Natural Killer (NK) cells,neutrophils, and macrophages) enables these cytotoxic effector cells tobind specifically to an antigen-bearing cells and subsequently kill thecells with cytotoxins. Specific high-affinity IgG antibodies directed tothe surface of cells “arm” the cytotoxic cells and are required for suchkilling. Lysis of the cell is extracellular, requires directcell-to-cell contact, and does not involve complement.

Another process encompassed by the term effector function is complementdependent cytotoxicity (hereinafter referred to as “CDC”) which refersto a biochemical event of cell destruction by the complement system. Thecomplement system is a complex system of proteins found in normal bloodplasma that combines with antibodies to destroy pathogenic bacteria andother foreign cells.

Still another process encompassed by the term effector function isantibody dependent cell-mediated phagocytosis (ADCP) which refers to acell-mediated reaction wherein nonspecific cytotoxic cells that expressone or more effector ligands recognize bound antibody on a cell andsubsequently cause phagocytosis of the cell.

It is contemplated that Fc variant antibodies are characterized by invitro functional assays for determining one or more FcγR mediatedeffector cell functions. In certain embodiments, Fc variant antibodieshave similar binding properties and effector cell functions in in vivomodels (such as those described and disclosed herein) as those in invitro based assays. However, the present invention does not exclude Fcvariant antibodies that do not exhibit the desired phenotype in in vitrobased assays but do exhibit the desired phenotype in vivo.

In certain embodiments, an antibody having an Fc variant has enhancedcytotoxicity or phagocytosis activity (e.g., ADCC, CDC and ADCP)relative to an antibody with a native Fc region. In a specificembodiment, an Fc variant antibody has cytotoxicity or phagocytosisactivity that is at least 2 fold, or at least 3 fold, or at least 5 foldor at least 10 fold or at least 50 fold or at least 100 fold, or up to50 fold, or up to 75 fold, or up to 100 fold, or up to 200 fold, or isbetween 2 fold and 10 fold, or between 5 fold and 50 fold, or between 25fold and 100 fold, or between 75 fold and 200 fold, or between 100 and200 fold, greater than that of a native Fc antibody. Alternatively, anFc variant antibody has reduced cytotoxicity or phagocytosis activityrelative to a native Fc antibody. In a specific embodiment, an Fcvariant antibody has cytotoxicity or phagocytosis activity that is atleast 2 fold, or at least 3 fold, or at least 5 fold or at least 10 foldor at least 50 fold or at least 100 fold, or up to 50 fold, or up to 75fold, or up to 100 fold, or up to 200 fold, or is between 2 fold and 10fold, or between 5 fold and 50 fold, or between 25 fold and 100 fold, orbetween 75 fold and 200 fold, or between 100 and 200 fold, lower thanthat of a native Fc antibody.

In certain embodiments, Fc variant antibodies exhibit decreased ADCCactivities as compared to a native Fc antibody. In another embodiment,Fc variant antibodies exhibit ADCC activities that are at least 2 fold,or at least 3 fold, or at least 5 fold or at least 10 fold or at least50 fold or at least 100 fold, or up to 50 fold, or up to 75 fold, or upto 100 fold, or up to 200 fold, or is between 2 fold and 10 fold, orbetween 5 fold and 50 fold, or between 25 fold and 100 fold, or between75 fold and 200 fold, or between 100 and 200 fold, less than that of anative Fc antibody. In still another embodiment, Fc variant antibodiesexhibit ADCC activities that are reduced by at least 10%, or at least20%, or by at least 30%, or by at least 40%, or by at least 50%, or byat least 60%, or by at least 70%, or by at least 80%, or by at least90%, or by at least 100%, or by at least 200%, or by at least 300%, orby at least 400%, or by at least 500%, relative to a native Fc antibody.In certain embodiments, Fc variant antibodies have no detectable ADCCactivity. In specific embodiments, the reduction and/or ablatement ofADCC activity may be attributed to the reduced affinity Fc variantantibodies exhibit for Fc ligands and/or receptors.

In an alternative embodiment, Fc variant antibodies exhibit increasedADCC activities as compared to a native Fc antibody. In anotherembodiment, Fc variant antibodies exhibit ADCC activities that are atleast 2 fold, or at least 3 fold, or at least 5 fold or at least 10 foldor at least 50 fold or at least 100 fold greater than that of a nativeFc antibody. In still another embodiment, Fc variant antibodies exhibitADCC activities that are increased by at least 10%, or at least 20%, orby at least 30%, or by at least 40%, or by at least 50%, or by at least60%, or by at least 70%, or by at least 80%, or by at least 90%, or byat least 100%, or by at least 200%, or by at least 300%, or by at least400%, or by at least 500% relative to a native Fc antibody. In specificembodiments, the increased ADCC activity may be attributed to theincreased affinity Fc variant antibodies exhibit for Fc ligands and/orreceptors.

In a specific embodiment, an Fc variant antibody has enhanced binding tothe Fc receptor FcγRIIIA and has enhanced ADCC activity relative to anative Fc antibody. In other embodiments, the Fc variant antibody hasboth enhanced ADCC activity and enhanced serum half-life relative to anative Fc antibody. In another specific embodiment, an Fc variantantibody has reduced binding to the Fc receptor FcγRIIIA and has reducedADCC activity relative to a native Fc antibody. In other embodiments,the Fc variant antibody has both reduced ADCC activity and enhancedserum half-life relative to a native Fc antibody.

In certain embodiments, the cytotoxicity is mediated by CDC wherein theFc variant antibody has either enhanced or decreased CDC activityrelative to a native Fc antibody. The complement activation pathway isinitiated by the binding of the first component of the complement system(C1q) to a molecule, an antibody for example, complexed with a cognateantigen. To assess complement activation, a CDC assay, e.g. as describedin Gazzano-Santoro et al. (1996) J. Immunol. Methods, 202:163, may beperformed.

In one embodiment, antibodies of the invention exhibit increased CDCactivity as compared to a native Fc antibody. In another embodiment, Fcvariant antibodies exhibit CDC activity that is at least 2 fold, or atleast 3 fold, or at least 5 fold or at least 10 fold or at least 50 foldor at least 100 fold, or up to 50 fold, or up to 75 fold, or up to 100fold, or up to 200 fold, or is between 2 fold and 10 fold, or between 5fold and 50 fold, or between 25 fold and 100 fold, or between 75 foldand 200 fold, or between 100 and 200 fold more than that of an native Fcantibody. In still another embodiment, Fc variant antibodies exhibit CDCactivity that is increased by at least 10%, or at least 20%, or by atleast 30%, or by at least 40%, or by at least 50%, or by at least 60%,or by at least 70%, or by at least 80%, or by at least 90%, or by atleast 100%, or by at least 200%, or by at least 300%, or by at least400%, or by at least 500% relative to a native Fc antibody. In specificembodiments, the increase of CDC activity may be attributed to theincreased affinity Fc variant antibodies exhibit for C1q.

Antibodies of the invention may exhibit increased CDC activity ascompared to a native Fc antibody by virtue of COMPLEGENT® Technology(Kyowa Hakko Kirin Co., Ltd.), which enhances one of the majormechanisms of action of an antibody, CDC. With an approach calledisotype chimerism, in which portions of IgG3, an antibody's isotype, areintroduced into corresponding regions of IgG1, the standard isotype fortherapeutic antibodies, COMPLEGENT® Technology significantly enhancesCDC activity beyond that of either IgG1 or IgG3, while retaining thedesirable features of IgG1, such as ADCC, PK profile and Protein Abinding. In addition, it can be used together with POTELLIGENT®Technology, creating an even superior therapeutic Mab (ACCRETAMAB®) withenhanced ADCC and CDC activities

Fc variant antibody of the invention may have enhanced ADCC activity andenhanced serum half-life relative to a native Fc antibody.

Fc variant antibody of the invention may CDC activity and enhanced serumhalf-life relative to a native Fc antibody.

Fc variant antibody of the invention may have enhanced ADCC activity,enhanced CDC activity and enhanced serum half-life relative to a nativeFc antibody.

The serum half-life of proteins having Fc regions may be increased byincreasing the binding affinity of the Fc region for FcRn. The term“antibody half-life” as used herein means a pharmacokinetic property ofan antibody that is a measure of the mean survival time of antibodymolecules following their administration. Antibody half-life can beexpressed as the time required to eliminate 50 percent of a knownquantity of immunoglobulin from the patient's body (or other mammal) ora specific compartment thereof, for example, as measured in serum, i.e.,circulating half-life, or in other tissues. Half-life may vary from oneimmunoglobulin or class of immunoglobulin to another. In general, anincrease in antibody half-life results in an increase in mean residencetime (MRT) in circulation for the antibody administered.

The increase in half-life allows for the reduction in amount of druggiven to a patient as well as reducing the frequency of administration.To increase the serum half-life of the antibody, one may incorporate asalvage receptor binding epitope into the antibody (especially anantibody fragment) as described in U.S. Pat. No. 5,739,277, for example.As used herein, the term “salvage receptor binding epitope” refers to anepitope of the Fc region of an IgG molecule (e.g., IgG1, IgG2, IgG3, orIgG4) that is responsible for increasing the in vivo serum half-life ofthe IgG molecule.

Alternatively, antibodies of the invention with increased half-lives maybe generated by modifying amino acid residues identified as involved inthe interaction between the Fc and the FcRn receptor (see, for examples,U.S. Pat. Nos. 6,821,505 and 7,083,784; and WO 09/058492). In addition,the half-life of antibodies of the invention may be increase byconjugation to PEG or Albumin by techniques widely utilized in the art.In some embodiments antibodies having Fc variant regions of theinvention have an increased half-life of about 5%, about 10%, about 15%,about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about50%, about 60%, about 65%, about 70%, about 80%, about 85%, about 90%,about 95%, about 100%, about 125%, about 150% or more as compared to anantibody having a native Fc region. In some embodiments antibodieshaving Fc variant regions have an increased half-life of about 2 fold,about 3 fold, about 4 fold, about 5 fold, about 10 fold, about 20 fold,about 50 fold or more, or up to about 10 fold, about 20 fold, or about50 fold, or between 2 fold and 10 fold, or between 5 fold and 25 fold,or between 15 fold and 50 fold, as compared to an antibody with a nativeFc region.

In one embodiment, the present invention provides Fc variants, whereinthe Fc region includes a modification (e.g., amino acid substitutions,amino acid insertions, amino acid deletions) at one or more positionsselected from 221, 225, 228, 234, 235, 236, 237, 238, 239, 240, 241,243, 244, 245, 247, 250, 251, 252, 254, 255, 256, 257, 262, 263, 264,265, 266, 267, 268, 269, 279, 280, 284, 292, 296, 297, 298, 299, 305,308, 313, 316, 318, 320, 322, 325, 326, 327, 328, 329, 330, 331, 332,333, 334, 339, 341, 343, 370, 373, 378, 392, 416, 419, 421, 428, 433,434, 435, 436, 440, and 443 as numbered by the EU index as set forth inKabat. Optionally, the Fc region may include a modification atadditional and/or alternative positions known to one skilled in the art(see, e.g., U.S. Pat. Nos. 5,624,821; 6,277,375; 6,737,056; 7,083,784;7,317,091; 7,217,797; 7,276,585; 7,355,008; 2002/0147311; 2004/0002587;2005/0215768; 2007/0135620; 2007/0224188; 2008/0089892; WO 94/29351; andWO 99/58572). Additional, useful amino acid positions and specificsubstitutions are exemplified in Tables 2, and 6-10 of U.S. Pat. No.6,737,056; the tables presented in FIG. 41 of US 2006/024298; the tablespresented in FIGS. 5, 12, and 15 of US 2006/235208; the tables presentedin FIGS. 8, 9 and 10 of US 2006/0173170 and the tables presented inFIGS. 8-10, 13 and 14 of WO 09/058492.

In a specific embodiment, the present invention provides an Fc variant,wherein the Fc region includes at least one substitution selected from221K, 221Y, 225E, 225K, 225W, 228P, 234D, 234E, 234N, 234Q, 234T, 234H,234Y, 234I, 234V, 234F, 235A, 235D, 235R, 235W, 235P, 235S, 235N, 235Q,235T, 235H, 235Y, 235I, 235V, 235E, 235F, 236E, 237L, 237M, 237P, 239D,239E, 239N, 239Q, 239F, 239T, 239H, 239Y, 240I, 240A, 240T, 240M, 241W,241L, 241Y, 241E, 241R. 243W, 243L 243Y, 243R, 243Q, 244H, 245A, 247L,247V, 247G, 250E, 250Q, 251F, 252L, 252Y, 254S, 254T, 255L, 256E, 256F,256M, 257C, 257M, 257N, 262I, 262A, 262T, 262E, 263I, 263A, 263T, 263M,264L, 264I, 264W, 264T, 264R, 264F, 264M, 264Y, 264E, 265A, 265G, 265N,265Q, 265Y, 265F, 265V, 265I, 265L, 265H, 265T, 266I, 266A, 266T, 266M,267Q, 267L, 268E, 269H, 269Y, 269F, 269R, 270E, 280A, 284M, 292P, 292L,296E, 296Q, 296D, 296N, 296S, 296T, 296L, 296I, 296H, 296G, 297S, 297D,297E, 298A, 298H, 298I, 298T, 298F, 299I, 299L, 299A, 299S, 299V, 299H,299F, 299E, 305I, 308F, 313F, 316D, 318A, 318S, 320A, 320S, 322A, 322S,325Q, 325L, 325I, 325D, 325E, 325A, 325T, 325V, 325H, 326A, 326D, 326E,326G, 326M, 326V, 327G, 327W, 327N, 327L, 328S, 328M, 328D, 328E, 328N,328Q, 328F, 328I, 328V, 328T, 328H, 328A, 329F, 329H, 329Q, 330K, 330G,330T, 330C, 330L, 330Y, 330V, 330I, 330F, 330R, 330H, 331G, 331A, 331L,331M, 331F, 331W, 331K, 331Q, 331E, 331S, 331V, 331I, 331C, 331Y, 331H,331R, 331N, 331D, 331T, 332D, 332S, 332W, 332F, 332E, 332N, 332Q, 332T,332H, 332Y, 332A, 333A, 333D, 333G, 333Q, 333S, 333V, 334A, 334E, 334H,334L, 334M, 334Q, 334V, 334Y, 339T, 370E, 370N, 378D, 392T, 396L, 416G,419H, 421K, 428L, 428F, 433K, 433L, 434A, 424F, 434W, 434Y, 436H, 440Yand 443W as numbered by the EU index as set forth in Kabat. Optionally,the Fc region may include additional and/or alternative amino acidsubstitutions known to one skilled in the art including but not limitedto those exemplified in Tables 2, and 6-10 of U.S. Pat. No. 6,737,056;the tables presented in FIG. 41 of US 2006/024298; the tables presentedin FIGS. 5, 12, and 15 of US 2006/235208; the tables presented in FIGS.8, 9 and 10 of US 2006/0173170 and the tables presented in FIGS. 8, 9and 10 of WO 09/058492.

In a specific embodiment, the present invention provides an Fc variantantibody, wherein the Fc region includes at least one modification(e.g., amino acid substitutions, amino acid insertions, amino aciddeletions) at one or more positions selected from 228, 234, 235 and 331as numbered by the EU index as set forth in Kabat. In one embodiment,the modification is at least one substitution selected from 228P, 234F,235E, 235F, 235Y, and 331S as numbered by the EU index as set forth inKabat.

In another specific embodiment, the present invention provides an Fcvariant antibody, wherein the Fc region is an IgG4 Fc region andincludes at least one modification at one or more positions selectedfrom 228 and 235 as numbered by the EU index as set forth in Kabat. Instill another specific embodiment, the Fc region is an IgG4 Fc regionand the non-naturally occurring amino acids are selected from 228P, 235Eand 235Y as numbered by the EU index as set forth in Kabat.

In another specific embodiment, the present invention provides an Fcvariant, wherein the Fc region includes at least one non-naturallyoccurring amino acid at one or more positions selected from 239, 330 and332 as numbered by the EU index as set forth in Kabat. In oneembodiment, the modification is at least one substitution selected from239D, 330L, 330Y, and 332E as numbered by the EU index as set forth inKabat.

In a specific embodiment, the present invention provides an Fc variantantibody, wherein the Fc region includes at least one non-naturallyoccurring amino acid at one or more positions selected from 252, 254,and 256 as numbered by the EU index as set forth in Kabat. In oneembodiment, the modification is at least one substitution selected from252Y, 254T and 256E as numbered by the EU index as set forth in Kabat.In particularly preferred antibodies of the invention, the modificationis three substitutions 252Y, 254T and 256E as numbered by the EU indexas set forth in Kabat (known as “YTE”), see U.S. Pat. No. 7,083,784.

In certain embodiments the effector functions elicited by IgG antibodiesstrongly depend on the carbohydrate moiety linked to the Fc region ofthe protein (Ferrara et al. (2006) Biotechnology and Bioengineering.93:851-861). Thus, glycosylation of the Fc region can be modified toincrease or decrease effector function (see for examples, Umana et al.(1999) Nat. Biotechnol. 17:176-180; Davies et al. (2001) BiotechnolBioeng. 74:288-294; Shields et al. (2002) J Biol Chem. 277:26733-26740;Shinkawa et al. (2003) J Biol Chem. 278:3466-3473; U.S. Pat. Nos.6,602,684; 6,946,292; 7,064,191; 7,214,775; 7,393,683; 7,425,446;7,504,256; U.S. Publication. Nos. 2003/0157108; 2003/0003097;2009/0010921; Potillegent™ technology (Biowa, Inc. Princeton, N.J.);GlycoMAb™ glycosylation engineering technology (GLYCART biotechnologyAG, Zurich, Switzerland)). Accordingly, in one embodiment the Fc regionsof antibodies of the invention include altered glycosylation of aminoacid residues. In another embodiment, the altered glycosylation of theamino acid residues results in lowered effector function. In anotherembodiment, the altered glycosylation of the amino acid residues resultsin increased effector function. In a specific embodiment, the Fc regionhas reduced fucosylation. In another embodiment, the Fc region isafucosylated (see for examples, U.S. Patent Application Publication No.2005/0226867). In one aspect, these antibodies with increased effectorfunction, specifically ADCC, as generated in host cells (e.g., CHOcells, Lemna minor) engineered to produce highly defucosylated antibodywith over 100-fold higher ADCC compared to antibody produced by theparental cells (Mori et al. (2004) Biotechnol Bioeng. 88:901-908; Cox etal. (2006) Nat Biotechnol. 24:1591-7).

Addition of sialic acid to the oligosaccharides on IgG molecules canenhance their anti-inflammatory activity and alters their cytotoxicity(Keneko et al. (2006) Science. 313:670-673; Scallon et al. (2007) Mol.Immuno. 44(7):1524-34). The studies referenced above demonstrate thatIgG molecules with increased sialylation have anti-inflammatoryproperties whereas IgG molecules with reduced sialylation have increasedimmunostimulatory properties (e.g., increase ADCC activity). Therefore,an antibody can be modified with an appropriate sialylation profile fora particular therapeutic application (US Publication No. 2009/0004179and International Publication No. WO 2007/005786).

In one embodiment, the Fc regions of antibodies of the invention includean altered sialylation profile compared to the native Fc region. In oneembodiment, the Fc regions of antibodies of the invention include anincreased sialylation profile compared to the native Fc region. Inanother embodiment, the Fc regions of antibodies of the inventioninclude a decreased sialylation profile compared to the native Fcregion.

In one embodiment, the Fc variants of the present invention may becombined with other known Fc variants such as those disclosed in Ghetieet al. (1997) Nat Biotech. 15:637-40; Duncan et al. (1988) Nature.332:563-564; Lund et al. (1991) J. Immunol. 147:2657-2662; Lund et al.(1992) Mol Immunol. 29:53-59; Alegre et al. (1994) Transplantation.57:1537-1543; Hutchins et al. (1995) Proc Natl. Acad. Sci. USA.92:11980-11984; Jefferis et al. (1995) Immunol Lett. 44:111-117; Lund etal. (1995) Faseb. J. 9:115-119; Jefferis et al. (1996) Immunol. Lett.54:101-104; Lund et al. (1996) J. Immunol. 157:4963-4969; Armour et al.(1999) Eur. J. Immunol. 29:2613-2624; Idusogie et al. (2000) J. Immunol.164:4178-4184; Reddy et al. (2000) J. Immunol. 164:1925-1933; Xu et al.(2000) Cell. Immunol. 200:16-26; Idusogie et al. (2001) J. Immunol.166:2571-2575; Shields et al. (2001) J. Biol. Chem. 276:6591-6604;Jefferis et al. (2002) Immunol. Lett. 82:57-65; Presta et al. (2002)Biochem. Soc. Trans. 30:487-490); U.S. Pat. Nos. 5,624,821; 5,885,573;5,677,425; 6,165,745; 6,277,375; 5,869,046; 6,121,022; 5,624,821;5,648,260; 6,528,624; 6,194,551; 6,737,056; 7,122,637; 7,183,387;7,332,581; 7,335,742; 7,371,826; 6,821,505; 6,180,377; 7,317,091;7,355,008; 2004/0002587; and WO 99/58572. Other modifications and/orsubstitutions and/or additions and/or deletions of the Fc domain will bereadily apparent to one skilled in the art.

Glycosylation

In addition to the ability of glycosylation to alter the effectorfunction of antibodies, modified glycosylation in the variable regioncan alter the affinity of the antibody for antigen. In one embodiment,the glycosylation pattern in the variable region of the presentantibodies is modified. For example, an aglycoslated antibody can bemade (i.e., the antibody lacks glycosylation). Glycosylation can bealtered to, for example, increase the affinity of the antibody forantigen. Such carbohydrate modifications can be accomplished by, forexample, altering one or more sites of glycosylation within the antibodysequence. For example, one or more amino acid substitutions can be madethat result in elimination of one or more variable region frameworkglycosylation sites to thereby eliminate glycosylation at that site.Such aglycosylation may increase the affinity of the antibody forantigen. Such an approach is described in further detail in U.S. Pat.Nos. 5,714,350 and 6,350,861. One or more amino acid substitutions canalso be made that result in elimination of a glycosylation site presentin the Fc region (e.g., Asparagine 297 of IgG). Furthermore,aglycosylated antibodies may be produced in bacterial cells which lackthe necessary glycosylation machinery.

Antibody Conjugates

In certain embodiments, the antibodies of the invention are conjugatedor covalently attached to a substance using methods well known in theart. In one embodiment, the attached substance is a therapeutic agent, adetectable label (also referred to herein as a reporter molecule) or asolid support. Suitable substances for attachment to antibodies include,but are not limited to, an amino acid, a peptide, a protein, apolysaccharide, a nucleoside, a nucleotide, an oligonucleotide, anucleic acid, a hapten, a drug, a hormone, a lipid, a lipid assembly, asynthetic polymer, a polymeric microparticle, a biological cell, avirus, a fluorophore, a chromophore, a dye, a toxin, a hapten, anenzyme, an antibody, an antibody fragment, a radioisotope, solidmatrixes, semi-solid matrixes and combinations thereof. Methods forconjugation or covalently attaching another substance to an antibody arewell known in the art.

In certain embodiments, the antibodies of the invention are conjugatedto a solid support. Antibodies may be conjugated to a solid support aspart of the screening and/or purification and/or manufacturing process.Alternatively antibodies of the invention may be conjugated to a solidsupport as part of a diagnostic method or composition. A solid supportsuitable for use in the present invention is typically substantiallyinsoluble in liquid phases. A large number of supports are available andare known to one of ordinary skill in the art. Thus, solid supportsinclude solid and semi-solid matrixes, such as aerogels and hydrogels,resins, beads, biochips (including thin film coated biochips),microfluidic chip, a silicon chip, multi-well plates (also referred toas microtitre plates or microplates), membranes, conducting andnon-conducting metals, glass (including microscope slides) and magneticsupports. More specific examples of solid supports include silica gels,polymeric membranes, particles, derivatized plastic films, glass beads,cotton, plastic beads, alumina gels, polysaccharides such as Sepharose,poly(acrylate), polystyrene, poly(acrylamide), polyol, agarose, agar,cellulose, dextran, starch, FICOLL, heparin, glycogen, amylopectin,mannan, inulin, nitrocellulose, diazocellulose, polyvinylchloride,polypropylene, polyethylene (including poly(ethylene glycol)), nylon,latex bead, magnetic bead, paramagnetic bead, superparamagnetic bead,starch and the like.

In some embodiments, the solid support may include a reactive functionalgroup, including, but not limited to, hydroxyl, carboxyl, amino, thiol,aldehyde, halogen, nitro, cyano, amido, urea, carbonate, carbamate,isocyanate, sulfone, sulfonate, sulfonamide, sulfoxide, etc., forattaching the antibodies of the invention.

A suitable solid phase support can be selected on the basis of desiredend use and suitability for various synthetic protocols. For example,where amide bond formation is desirable to attach the antibodies of theinvention to the solid support, resins generally useful in peptidesynthesis may be employed, such as polystyrene (e.g., PAM-resin obtainedfrom Bachem Inc., Peninsula Laboratories, etc.), POLYHIPE™ resin(obtained from Aminotech, Canada), polyamide resin (obtained fromPeninsula Laboratories), polystyrene resin grafted with polyethyleneglycol (TentaGel™, Rapp Polymere, Tubingen, Germany),polydimethyl-acrylamide resin (available from Milligen/Biosearch,California), or PEGA beads (obtained from Polymer Laboratories).

In certain embodiments, the antibodies of the invention are conjugatedto labels for purposes of diagnostics and other assays wherein theantibody and/or its associated ligand may be detected. A labelconjugated to an antibody and used in the present methods andcompositions described herein, is any chemical moiety, organic orinorganic, that exhibits an absorption maximum at wavelengths greaterthan 280 nm, and retains its spectral properties when covalentlyattached to an antibody. Labels include, without limitation, achromophore, a fluorophore, a fluorescent protein, a phosphorescent dye,a tandem dye, a particle, a hapten, an enzyme and a radioisotope.

In certain embodiments, the antibodies are conjugated to a fluorophore.As such, fluorophores used to label antibodies of the invention include,without limitation; a pyrene (including any of the correspondingderivative compounds disclosed in U.S. Pat. No. 5,132,432), ananthracene, a naphthalene, an acridine, a stilbene, an indole orbenzindole, an oxazole or benzoxazole, a thiazole or benzothiazole, a4-amino-7-nitrobenz-2-oxa-1,3-diazole (NBD), a cyanine (including anycorresponding compounds in U.S. Pat. Nos. 6,977,305 and 6,974,873), acarbocyanine (including any corresponding compounds in U.S. Ser. No.09/557,275; U.S. Pat. Nos. 4,981,977; 5,268,486; 5,569,587; 5,569,766;5,486,616; 5,627,027; 5,808,044; 5,877,310; 6,002,003; 6,004,536;6,008,373; 6,043,025; 6,127,134; 6,130,094; 6,133,445; and publicationsWO 02/26891, WO 97/40104, WO 99/51702, WO 01/21624; EP 1 065 250 A1), acarbostyryl, a porphyrin, a salicylate, an anthranilate, an azulene, aperylene, a pyridine, a quinoline, a borapolyazaindacene (including anycorresponding compounds disclosed in U.S. Pat. Nos. 4,774,339;5,187,288; 5,248,782; 5,274,113; and 5,433,896), a xanthene (includingany corresponding compounds disclosed in U.S. Pat. Nos. 6,162,931;6,130,101; 6,229,055; 6,339,392; 5,451,343; 5,227,487; 5,442,045;5,798,276; 5,846,737; 4,945,171; U.S. Ser. Nos. 09/129,015 and09/922,333), an oxazine (including any corresponding compounds disclosedin U.S. Pat. No. 4,714,763) or a benzoxazine, a carbazine (including anycorresponding compounds disclosed in U.S. Pat. No. 4,810,636), aphenalenone, a coumarin (including an corresponding compounds disclosedin U.S. Pat. Nos. 5,696,157; 5,459,276; 5,501,980 and 5,830,912), abenzofuran (including an corresponding compounds disclosed in U.S. Pat.Nos. 4,603,209 and 4,849,362) and benzphenalenone (including anycorresponding compounds disclosed in U.S. Pat. No. 4,812,409) andderivatives thereof. As used herein, oxazines include resorufins(including any corresponding compounds disclosed in U.S. Pat. No.5,242,805), aminooxazinones, diaminooxazines, and theirbenzo-substituted analogs.

In a specific embodiment, the fluorophores conjugated to the antibodiesdescribed herein include xanthene (rhodol, rhodamine, fluorescein andderivatives thereof) coumarin, cyanine, pyrene, oxazine andborapolyazaindacene. In other embodiments, such fluorophores aresulfonated xanthenes, fluorinated xanthenes, sulfonated coumarins,fluorinated coumarins and sulfonated cyanines. Also included are dyessold under the tradenames, and generally known as, ALEXA FLUOR®,DyLight, CY® Dyes, BODIPY®, OREGON GREEN®, PACIFIC BLUE™, IRDYE®, FAM,FITC, and ROX™.

The choice of the fluorophore attached to the antibody will determinethe absorption and fluorescence emission properties of the conjugatedantibody. Physical properties of a fluorophore label that can be usedfor antibody and antibody bound ligands include, but are not limited to,spectral characteristics (absorption, emission and stokes shift),fluorescence intensity, lifetime, polarization and photo-bleaching rate,or combination thereof. All of these physical properties can be used todistinguish one fluorophore from another, and thereby allow formultiplexed analysis. In certain embodiments, the fluorophore has anabsorption maximum at wavelengths greater than 480 nm. In otherembodiments, the fluorophore absorbs at or near 488 nm to 514 nm(particularly suitable for excitation by the output of the argon-ionlaser excitation source) or near 546 nm (particularly suitable forexcitation by a mercury arc lamp). In other embodiment a fluorophore canemit in the NIR (near infrared region) for tissue or whole organismapplications. Other desirable properties of the fluorescent label mayinclude cell permeability and low toxicity, for example if labeling ofthe antibody is to be performed in a cell or an organism (e.g., a livinganimal).

In certain embodiments, an enzyme is a label and is conjugated to anantibody described herein. Enzymes are desirable labels becauseamplification of the detectable signal can be obtained resulting inincreased assay sensitivity. The enzyme itself does not produce adetectable response but functions to break down a substrate when it iscontacted by an appropriate substrate such that the converted substrateproduces a fluorescent, colorimetric or luminescent signal. Enzymesamplify the detectable signal because one enzyme on a labeling reagentcan result in multiple substrates being converted to a detectablesignal. The enzyme substrate is selected to yield the preferredmeasurable product, e.g. colorimetric, fluorescent or chemiluminescence.Such substrates are extensively used in the art and are well known byone skilled in the art.

In one embodiment, colorimetric or fluorogenic substrate and enzymecombination uses oxidoreductases such as horseradish peroxidase and asubstrate such as 3,3′-diaminobenzidine (DAB) and3-amino-9-ethylcarbazole (AEC), which yield a distinguishing color(brown and red, respectively). Other colorimetric oxidoreductasesubstrates that yield detectable products include, but are not limitedto: 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS),o-phenylenediamine (OPD), 3,3′,5,5′-tetramethylbenzidine (TMB),o-dianisidine, 5-aminosalicylic acid, 4-chloro-1-naphthol. Fluorogenicsubstrates include, but are not limited to, homovanillic acid or4-hydroxy-3-methoxyphenylacetic acid, reduced phenoxazines and reducedbenzothiazines, including Amplex® Red reagent and its variants (U.S.Pat. No. 4,384,042) and reduced dihydroxanthenes, includingdihydrofluoresceins (U.S. Pat. No. 6,162,931) and dihydrorhodaminesincluding dihydrorhodamine 123. Peroxidase substrates that are tyramides(U.S. Pat. Nos. 5,196,306; 5,583,001 and 5,731,158) represent a uniqueclass of peroxidase substrates in that they can be intrinsicallydetectable before action of the enzyme but are “fixed in place” by theaction of a peroxidase in the process described as tyramide signalamplification (TSA). These substrates are extensively utilized to labelantigen in samples that are cells, tissues or arrays for theirsubsequent detection by microscopy, flow cytometry, optical scanning andfluorometry.

In another embodiment, a colorimetric (and in some cases fluorogenic)substrate and enzyme combination uses a phosphatase enzyme such as anacid phosphatase, an alkaline phosphatase or a recombinant version ofsuch a phosphatase in combination with a colorimetric substrate such as5-bromo-6-chloro-3-indolyl phosphate (BCIP), 6-chloro-3-indolylphosphate, 5-bromo-6-chloro-3-indolyl phosphate, p-nitrophenylphosphate, or o-nitrophenyl phosphate or with a fluorogenic substratesuch as 4-methylumbelliferyl phosphate,6,8-difluoro-7-hydroxy-4-methylcoumarinyl phosphate (DiFMUP, U.S. Pat.No. 5,830,912) fluorescein diphosphate, 3-O-methylfluorescein phosphate,resorufin phosphate, 9H-(1,3-dichloro-9,9-dimethylacridin-2-one-7-yl)phosphate (DDAO phosphate), or ELF 97, ELF 39 or related phosphates(U.S. Pat. Nos. 5,316,906 and 5,443,986).

Glycosidases, in particular beta-galactosidase, beta-glucuronidase andbeta-glucosidase, are additional suitable enzymes. Appropriatecolorimetric substrates include, but are not limited to,5-bromo-4-chloro-3-indolyl beta-D-galactopyranoside (X-gal) and similarindolyl galactosides, glucosides, and glucuronides, o-nitrophenylbeta-D-galactopyranoside (ONPG) and p-nitrophenylbeta-D-galactopyranoside. In one embodiment, fluorogenic substratesinclude resorufin beta-D-galactopyranoside, fluorescein digalactoside(FDG), fluorescein diglucuronide and their structural variants (U.S.Pat. Nos. 5,208,148; 5,242,805; 5,362,628; 5,576,424 and 5,773,236),4-methylumbelliferyl beta-D-galactopyranoside, carboxyumbelliferylbeta-D-galactopyranoside and fluorinated coumarinbeta-D-galactopyranosides (U.S. Pat. No. 5,830,912).

Additional enzymes include, but are not limited to, hydrolases such ascholinesterases and peptidases, oxidases such as glucose oxidase andcytochrome oxidases, and reductases for which suitable substrates areknown.

Enzymes and their appropriate substrates that produce chemiluminescenceare preferred for some assays. These include, but are not limited to,natural and recombinant forms of luciferases and aequorins.Chemiluminescence-producing substrates for phosphatases, glycosidasesand oxidases such as those containing stable dioxetanes, luminol,isoluminol and acridinium esters are additionally useful.

In another embodiment, haptens such as biotin, are also utilized aslabels. Biotin is useful because it can function in an enzyme system tofurther amplify the detectable signal, and it can function as a tag tobe used in affinity chromatography for isolation purposes. For detectionpurposes, an enzyme conjugate that has affinity for biotin is used, suchas avidin-HRP. Subsequently a peroxidase substrate is added to produce adetectable signal.

Haptens also include hormones, naturally occurring and synthetic drugs,pollutants, allergens, affector molecules, growth factors, chemokines,cytokines, lymphokines, amino acids, peptides, chemical intermediates,nucleotides and the like.

In certain embodiments, fluorescent proteins may be conjugated to theantibodies as a label. Examples of fluorescent proteins include greenfluorescent protein (GFP) and the phycobiliproteins and the derivativesthereof. The fluorescent proteins, especially phycobiliprotein, areparticularly useful for creating tandem dye labeled labeling reagents.These tandem dyes include a fluorescent protein and a fluorophore forthe purposes of obtaining a larger stokes shift wherein the emissionspectra is farther shifted from the wavelength of the fluorescentprotein's absorption spectra. This is particularly advantageous fordetecting a low quantity of antigen in a sample wherein the emittedfluorescent light is maximally optimized, in other words little to noneof the emitted light is reabsorbed by the fluorescent protein. For thisto work, the fluorescent protein and fluorophore function as an energytransfer pair wherein the fluorescent protein emits at the wavelengththat the fluorophore absorbs at and the fluorphore then emits at awavelength farther from the fluorescent proteins than could have beenobtained with only the fluorescent protein. A particularly usefulcombination is the phycobiliproteins disclosed in U.S. Pat. Nos.4,520,110; 4,859,582; 5,055,556 and the sulforhodamine fluorophoresdisclosed in U.S. Pat. No. 5,798,276, or the sulfonated cyaninefluorophores disclosed in U.S. Pat. Nos. 6,977,305 and 6,974,873; or thesulfonated xanthene derivatives disclosed in U.S. Pat. No. 6,130,101 andthose combinations disclosed in U.S. Pat. No. 4,542,104. Alternatively,the fluorophore functions as the energy donor and the fluorescentprotein is the energy acceptor.

In certain embodiments, the label is a radioactive isotope. Examples ofsuitable radioactive materials include, but are not limited to, iodine(121I, 123I, ¹²⁵I, ¹³¹I), carbon (¹⁴C), sulfur (³⁵S), tritium (³H),indium (¹¹¹In, ¹¹²In, ^(113m)In, ^(115m)In), technetium (⁹⁹Tc,^(99m)Tc), thallium (²⁰¹Ti), gallium (⁶⁸Ga, ⁶⁷Ga), palladium (¹⁰³Pd),molybdenum (⁹⁹Mo), xenon (¹³⁵Xe), fluorine (18F), ¹⁵³Sm, ¹⁷⁷Lu, ¹⁵⁹Gd,¹⁴⁹Pm, ¹⁴⁰La, ¹⁷⁵Yb, ¹⁶⁶Ho, ⁹⁰Y, ⁴⁷Sc, ¹⁸⁶Re, ¹⁸⁸Re, ¹⁴²Pr, ¹⁰⁵Rh, and⁹⁷Ru.

Medical Treatments and Uses

The antibodies and antigen binding fragments thereof of the inventionand variants thereof may be used for the treatment of influenza B virusinfection, for the prevention of influenza B virus infection; for thedetection, diagnosis and/or prognosis of influenza B virus infection; orcombinations thereof. In one embodiment, the antibodies and antigenbinding fragments thereof of the inventions and variants thereof may beused for the treatment of influenza A and influenza B infection, for theprevention of influenza A and influenza B; for the detection, diagnosisand/or prognosis of influenza A and influenza B infection; orcombinations thereof.

Methods of diagnosis may include contacting an antibody or an antibodyfragment with a sample. Such samples may be tissue samples taken from,for example, nasal passages, sinus cavities, salivary glands, lung,liver, pancreas, kidney, ear, eye, placenta, alimentary tract, heart,ovaries, pituitary, adrenals, thyroid, brain or skin. The methods ofdetection, diagnosis, and/or prognosis may also include the detection ofan antigen/antibody complex.

In one embodiment, the invention provides a method of treating a subjectby administering to the subject an effective amount of an antibody or anantigen binding fragment thereof, according to the invention, or apharmaceutical composition that includes the antibody or antigen bindingfragment thereof. In one embodiment, the antibody or antigen bindingfragment thereof is substantially purified (i.e., substantially freefrom substances that limit its effect or produce undesiredside-effects). In one embodiment, the antibody or antigen bindingfragment thereof of the invention is administered post-exposure, orafter the subject has been exposed to influenza B virus or is infectedwith influenza B virus. In one embodiment, the antibody or antigenbinding fragment thereof of the invention is administered post-exposure,or after the subject has been exposed to influenza B virus of Yamagataand/or Victoria lineage or is infected with influenza B virus ofYamagata and/or Victoria lineage. In one embodiment, the antibody orantigen binding fragment thereof of the invention is administeredpost-exposure, or after the subject has been exposed to at least oneinfluenza A virus subtype; influenza B virus of Yamagata lineage;influenza B virus of Victoria lineage, or combinations thereof; or isinfected with at least one influenza A virus subtype and/or influenza Bvirus of Yamagata and/or Victoria lineage.

In another embodiment, the antibody or antigen binding fragment thereofof the invention is administered pre-exposure, or to a subject that hasnot yet been exposed to influenza B virus or is not yet infected withinfluenza B virus. In another embodiment, the antibody or antigenbinding fragment thereof of the invention is administered pre-exposure,or to a subject that has not yet been exposed to influenza B virus ofYamagata and/or Victoria lineage or is not yet infected with influenza Bvirus of Yamagata and/or Victoria lineage. In another embodiment, theantibody or antigen binding fragment thereof of the invention isadministered pre-exposure, or to a subject that has not yet been exposedto influenza A virus; influenza B virus of Yamagata lineage; influenza Bvirus of Victoria lineage; or combinations thereof, or is not yetinfected with influenza A virus; influenza B virus of Yamagata lineage;influenza of Victoria lineage; or combinations thereof.

In one embodiment, the antibody or antigen binding fragment thereof ofthe invention is administered to a subject that is sero-negative for oneor more influenza B viruses. In one embodiment, the antibody or antigenbinding fragment thereof of the invention is administered to a subjectthat is sero-negative for one or more influenza B virus lineages. In oneembodiment, the antibody or antigen binding fragment thereof of theinvention is administered to a subject that is sero-negative for one ormore influenza A subtypes and/or one or more influenza B viruses.

In another embodiment, the antibody or antigen binding fragment thereofof the invention is administered to a subject that is sero-positive forone or more one or more influenza B viruses. In another embodiment, theantibody or antigen binding fragment thereof of the invention isadministered to a subject that is sero-positive for one or more one ormore influenza B virus lineages. In another embodiment, the antibody orantigen binding fragment thereof of the invention is administered to asubject that is sero-positive for one or more one or more influenza Avirus subtypes and/or one or more influenza B viruses. In oneembodiment, the antibody or antigen binding fragment thereof of theinvention is administered to a subject within 1, 2, 3, 4, 5 days ofinfection or symptom onset. In another embodiment, the antibody orantigen binding fragment thereof of the invention can be administered toa subject after 1, 2, 3, 4, 5, 6, or 7 days, and within 2, 3, 4, 5, 6,7, 8, 9 or 10 days after infection or symptom onset.

In one embodiment, the method reduces influenza B virus infection in asubject. In another embodiment, the method reduces influenza A virusinfection and/or influenza B virus infection in a subject. In anotherembodiment, the method prevents, reduces the risk or delays influenza Bvirus infection in a subject. In another embodiment, the methodprevents, reduces the risk or delays influenza A and/or influenza Bvirus infection in a subject. In one embodiment, the subject is ananimal. In one embodiment, the subject is a mammal. In a more particularembodiment, the subject is human. In one embodiment, the subjectincludes, but is not limited to, one who is particularly at risk of orsusceptible to influenza A and/or influenza B virus infection,including, for example, an immunocompromised subject.

Treatment can be a single dose schedule or a multiple dose schedule andthe antibody or antigen binding fragment thereof of the invention can beused in passive immunization or active vaccination.

In one embodiment, the antibody or antigen binding fragment thereof ofthe invention is administered to a subject in combination with one ormore antiviral medications. In one embodiment, the antibody or antigenbinding fragment thereof of the invention is administered to a subjectin combination with one or more small molecule antiviral medications.Small molecule antiviral medications include neuraminidase inhibitorssuch as oseltamivir (TAMIFLU®), zanamivir (RELENZA®) and adamantanessuch as Amantadine and rimantadine.

In another embodiment, the invention provides a composition for use as amedicament for the prevention or treatment of an influenza A and/orinfluenza B virus infection. In another embodiment, the inventionprovides the use of an antibody or antigen binding fragment thereof ofthe invention and/or a protein having an epitope to which an antibody orantigen binding fragment thereof of the invention binds in themanufacture of a medicament for treatment of a subject and/or diagnosisin a subject.

Antibodies and fragments thereof as described in the present inventionmay also be used in a kit for the diagnosis of influenza A virusinfection; influenza B virus infection; or combinations thereof.Further, epitopes capable of binding an antibody of the invention may beused in a kit for monitoring the efficacy of vaccination procedures bydetecting the presence of protective anti-influenza A and/or influenza Bvirus antibodies. Antibodies, antibody fragment, or variants andderivatives thereof, as described in the present invention may also beused in a kit for monitoring vaccine manufacture with the desiredimmunogenicity.

The invention also provides a method of preparing a pharmaceuticalcomposition, which includes the step of admixing a monoclonal antibodywith one or more pharmaceutically-acceptable carriers, wherein theantibody is a monoclonal antibody according to the invention describedherein.

Various delivery systems are known and can be used to administer theantibody or antigen binding fragment thereof of the invention,including, but not limited to, encapsulation in liposomes,microparticles, microcapsules, recombinant cells capable of expressingthe antibody or antibody fragment, receptor-mediated endocytosis,construction of a nucleic acid as part of a retroviral or other vector,etc. Methods of introduction include, but are not limited to,intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous,intranasal, epidural, and oral routes. In another embodiment, thevaccine can be administered as a DNA vaccine, for example usingelectroporation technology, including, but not limited to, in vivoelectroporation. The compositions may be administered by any convenientroute, for example by infusion or bolus injection, by absorption throughepithelial or mucocutaneous linings (e.g., oral mucosa, rectal andintestinal mucosa, etc.) and may be administered together with otherbiologically active agents, including, but not limited to small moleculeantiviral compositions. Administration can be systemic or local.Pulmonary administration can also be employed, e.g., by use of aninhaler or nebulizer, and formulation with an aerosolizing agent. In yetanother embodiment, the composition can be delivered in a controlledrelease system.

The present invention also provides pharmaceutical compositions. Suchcompositions include a therapeutically effective amount of an antibodyor antigen binding fragment thereof of the invention, and apharmaceutically acceptable carrier. The term “pharmaceuticallyacceptable” as used herein, means approved by a regulatory agency of theFederal or a state government or listed in the U.S. Pharmacopeia orother generally recognized pharmacopeia for use in animals, and moreparticularly in humans. The term “carrier” refers to a diluent,adjuvant, excipient, or vehicle with which the therapeutic isadministered. Such pharmaceutical carriers can be sterile liquids, suchas water and oils, including those of petroleum, animal, vegetable orsynthetic origin, such as peanut oil, soybean oil, mineral oil, sesameoil and the like. Water is a preferred carrier when the pharmaceuticalcomposition is administered intravenously. Saline solutions and aqueousdextrose and glycerol solutions can also be employed as liquid carriers,particularly for injectable solutions. Suitable pharmaceuticalexcipients include starch, glucose, lactose, sucrose, gelatin, malt,rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate,talc, sodium chloride, dried skim milk, glycerol, propylene, glycol,water, ethanol and the like. The composition, if desired, can alsocontain minor amounts of wetting or emulsifying agents, or pH bufferingagents. These compositions can take the form of solutions, suspensions,emulsion, tablets, pills, capsules, powders, sustained-releaseformulations and the like. The composition can be formulated as asuppository, with traditional binders and carriers such astriglycerides. Oral formulation can include standard carriers such aspharmaceutical grades of mannitol, lactose, starch, magnesium stearate,sodium saccharine, cellulose, magnesium carbonate, etc. In oneembodiment, the pharmaceutical composition contains a therapeuticallyeffective amount of the antibody or antigen binding fragment thereof,preferably in purified form, together with a suitable amount of carrierso as to provide the form for proper administration to the patient. Theformulation should suit the mode of administration.

Typically, for antibody therapeutics, the dosage administered to apatient is between about 0.1 mg/kg to 100 mg/kg of the patient's bodyweight.

EXAMPLES Example 1 Construction and Optimization of Human MonoclonalAntibodies Isolated from Memory B Cells

CD22+ IgG+ B cells were sorted from cryopreserved peripheral bloodmononuclear cells (PBMCs) of a donor selected for high neutralizingtiters against both B/Florida/4/2006 Yamagata lineage (B/FLA/06) andB/Brisbane/60/2008 Victoria Lineage (B/BNE/08) and immortalized at 3cells/well using Epstein Barr Virus (EBV), CpG oligodeoxynucleotide 2006and feeder cells. Culture supernatants containing antibodies wereharvested after 14 days and screened by microneutralization assay (MNA)that was modified from a previously described accelerated viralinhibition assay using neuraminidase activity (NA) as a read-out(Hassantoufighi et al. (2010) Vaccine. 28:790-7) to identify antibodyclones that could neutralize viruses from both Yamagata and Victoriainfluenza B lineages.

In brief 10 μl of culture supernatant was incubated with 400 TCID50 ofinfluenza B/BNE/08 (Victoria lineage) or B/FLA/06 (Yamagata lineage) forone hour at 37° C. Madin-Darby canine kidney (MDCK) cells were added tothe plates (20,000 cells per well), incubated for 4 hours, washed twicewith TPCK-trypsin containing medium and then incubated for 2 days at 37°C. After incubation, NA activity was measured by adding afluorescently-labelled substrate, methylumbelliferyl-N-acetyl neuraminicacid (MU-NANA) (Sigma) at 25 μl/well (10 μM) and plates were read with afluorometer.

Three B cell clones (FBC-39, FBD-56, and FBD-94) were found to haveneutralization activity against both influenza B Victoria and Yamagatalineages. The VH and VL genes of these clones were sequenced, and clonedinto IgG1 expression vectors. Recombinant antibodies were produced bytransient transfection of mammalian cell lines derived from HumanEmbryonic Kidney (HEK) or Chinese Hamster Ovary (CHO) cells.Supernatants from transfected cells were collected after 7-10 days ofculture, and antibodies (IgG) were affinity purified by Protein Achromatography, and dialyzed into Phosphate Buffered Saline (PBS).

An Ig BLAST algorithum was used to align the mAb sequences to a databaseof human antibody germline sequences. The the closest germline templateswere identified for each of the gene regions of the VH and VL (Table 6).Non-germlined amino acids were identified by aligning to these referencesequences.

TABLE 6 Identification of the closest human genes comprising the VH andVL VH V gene VH J gene VH D gene VL V gene VL J gene FBD-56 IGHV3-9*01IGHJ6*02 IGHD5-12*01 IGKV3-11*01 IGKJ5*01 FBD-94 IGHV3-9*01 IGHJ6*02IGHD6-13*01 IGKV3-11*01 IGKJ5*01 FBC-39 IGHV3-15*01 IGHJ6*02 IGHD3-3*01IGKV1-12*01 IGKJ2*01

FBC-39 Variant Construction:

In the FBC-39 antibody VL, there was only one non-germline frameworkresidue: F at position 87 in the light chain, wherein the germlinedamino acid is Y (or L87F(Y)), as numbered by Kabat (position 103 forIMGT numbering). The germlined sequence is referred to herein asFBC-39-L87Y. The non-germlined sequence is referred to as FBC-39-L87F.

In the FBC-39 antibody VH, there are 11 non-germlined Kabat definedframework residues: H6V(E), H27L(F), H28S(T), H30L(S), H68S(T), H77M(T),H79F(Y), H81H(Q), H82aS(N), H83R(K), and H93A(T), as numbered by Kabat.If using the IMGT definition of framework residues, there are 7non-germlined residues: H6V(E), H77S(T), H86M(T), H88F(Y), H90H(Q),H92S(N), and H95R(K).

A variant was constructed in which all 12 of the non-germlined Kabatdefined framework residues were reverted to the germline amino acid.This antibody construct demonstrated a significant reduction in theneutralizing activity and breadth of coverage for the Victoria lineageinfluenza B viruses, implying that one or more of the non-germlineresidue(s) are important for activity.

Three of the non-germlined framework residues, located at positions H27,H28, and H30, are in an area defined as the VH framework 1 by the Kabatsystem although they are considered part of the HCDR-1 by the IMGTsystem. Antibody variants were generated by reverting all non-germlinedKabat defined framework amino acids to their respective germlineresidues, except for these three positions: H27L(F), H28S(T), H30L(S),which were “wobbled” between germline residue and non-germline residueto generate seven heavy chain variants: FBC-39 LSL, FBC-39 FSL; FBC-39LTL; FBC-39 FTL; FBC-39-FSS; FBC-39-LTS; FBC-39-FTS, in which thegermline residues are underlined, such that FBC-39 FTS contains thethree germlined amino acids, and FBC-39 LSL contains the three wildtyperesidues at positions H27, H28, and H30.

Additionally, the germline residue N at H82 (H92 IMGT) created apotential deamidation site (NS) in the VH. Consequently, this wassubstituted with the wildtype S of FBC-39 in all seven variants, FBC-39LSL, FBC-39 FSL, FBC-39 LTL, FBC-39 FTL, FBC-39-FSS, FBC-39-LTS, andFBC-39-FTS. Additionally, all seven of the FBC-39 variants share thesame light chain sequence (FBC-39-L87Y), which differs from the FBC-39light chain by one amino acid.

The resulting antibody variants were expressed and purified as describedabove and further characterized.

Example 2 The Isolated Anti-HA Antibodies Bind to Both Influenza B HALineages

An HA ELISA binding assay was performed to determine the binding andcross-reactivity of the isolated antibodies. A 384-well Maxisorb ELISAplate (Nunc) was coated overnight at 4° C. with 0.5 μg/ml of recombinantHA derived from a Yamagata lineage strain B/FLA/06, or a Victorialineage strain B/BNE/08 in PBS. The plate was washed with PBS containing0.1% v/v Tween-20 to remove uncoated protein, and blocking solutioncontaining 1% (w/v) casein (Thermo Scientific) was added for 1 hour atroom temperature. The blocking solution was discarded and a 3-foldserial dilution in PBS of each of the anti-HA antibodies (FBC-39,FBD-56, and FBD-94) was added and incubated for 1 hour at roomtemperature. The plate was washed three times and bound antibodies weredetected using a peroxidase-conjugated mouse anti-human IgG antibody(Jackson). Antibody binding activity was calculated by either measuringthe chemiluminescent signal after addition of Supersignal Pico substrate(Thermo Scientific) or by measuring the color change at 450 nm afterincubation with Tetramethylbenzidine (TMB) one component substrate(available from Kirkegaard and Perry Laboratories, Inc. (KPL),Gaithersburg, Md.) followed by the addition of 2N sulfuric acid to stopthe reaction.

TABLE 7 Binding to rHA by ELISA (Ave EC₅₀, ng/ml) B/FL/06 (yam) B/BNE/08(vic) FBC-39 20 48 FBD-56 24 30 FBD-94 13 16

Table 7 shows the average EC₅₀ from three independent experiments. Allthree anti-HA IgGs (FBC-39, FBD-56 and FBD-94) bound recombinant HA fromboth influenza B lineages. Similar EC₅₀ values were observed withbetween all three antibodies against the Yamagata (B/FL/06) HA. A lowerEC₅₀ was observed with the Victoria (B/BNE/08) for FBD-94 than foreither FBD-56 or FBC-39.

The seven FBC-39 antibody germlined variants were tested for bindingactivity by ELISA. Table 8 shows the binding results of the unpurifiedanti-HA FBC-39 IgG variants, where the FBC-39 FTS contains the Kabatdefined framework germlined amino acids, and the FBC-39 LSL contains theKabat defined framework germined amino acids except wildtype residues atpositions H27, H28, and H30 (Kabat numbering). These results show thatall variants bound to the Yamagata lineage (B/FL/06) HA protein, butvariants containing an S residue at position H30 lost binding affinityfor the Victoria lineage (B/BNE/08) HA protein. Four of the variants,FBC-39 LSL, FSL, LTL, and FTL, showed equivalent or better bindingaffinity than FBC-39 to HA proteins from both lineages.

TABLE 8 Binding to rHA by ELISA (EC₅₀, ng/ml) B/FL/06 (yam) B/BNE/08(vic) FBC-39 22 186 FBC-39 LSL 21 152 FBC-39 FSL 14 273 FBC-39 LTL 17114 FBC-39 FTL 17 118 FBC-39 FSS 19 >1000 FBC-39 LTS 13 >1000 FBC-39 FTS26 >1000

Example 3 In Vitro Cross-Reactive Neutralizing Activity of Anti-Flu B HAIgGs Against Virus from Two Different Lineages

A similar microneutralization assay was used as described in Example 1to test for purified mAb activity. In brief, MDCK cells that werecultured in MEM medium (Invitrogen) supplemented with antibiotics,glutamine (complete MEM medium) and 10% (v/v) fetal bovine serum. 60TCID₅₀ (50% tissue culture infectious doses) of virus was added tothree-fold dilutions of antibody in a 384-well plate in complete MEMmedium containing 0.75 ug/ml TPCK treated trypsin (Worthington) induplicate wells, after 30 minutes incubation at room temperature, 2×10⁴cells/well were added to the plate. After incubation at 33° C. 5% CO₂incubator for approximately 40 hours, the NA activity was measured byadding a fluorescently-labelled substrate, methylumbelliferyl-N-acetylneuraminic acid (MU-NANA) (Sigma) to each well and incubated at 37° C.for 1 hr. Virus replication represented by NA activity was quantified byreading fluorescence using an Envision Fluorometer (PerkinElmer) usingthe following settings: excitation 355 nm, emission 460 nm; 10 flashesper well. The neutralization titer (50% inhibitory concentration [IC₅₀])is expressed as the final antibody concentration that reduced thefluorescence signal by 50% compared to cell control wells. Influenza Bvirus strains used in Table 9 are as listed below: B/Lee/40 (B/Lee/40);B/AA/66 (ca B/Ann Arbor/1/66); B/HK/72 (B/Hong Kong/5/72); B/BJ/97 (caB/Beijing/243/97 (victoria)), B/HK/01 (B/Hong Kong/330/2001 (victoria));B/MY/04 (B/Malaysia/2506/2004 (victoria)); B/BNE/08 (caB/Brisbane/60/2008 (victoria)); B/AA/94 (ca B/Ann Arbor/2/94(yamagata)); BNSI/98 (ca BNamanashi/166/98 (yamagata)); B/JHB/99 (caB/Johannesburg/5/99 (yamagata)); B/SC/99 (B/Sichuan/379/99 (yamagata));B/FL/06 (B/Florida/4/2006 (yamagata)).

TABLE 9 Neutralization (Ave IC₅₀ ug/ml) lineage virus strain FBD-56FBD-94 FBC39 FBC-39 LSL FBC-39 FSL FBC-39 LTL FBC-39 FTL untypedB/Lee/40 0.004 0.009 0.021 0.014 0.011 0.010 0.013 B/AA/66 0.035 0.0140.061 0.027 0.034 0.023 0.026 B/HK/72 0.051 0.017 0.026 0.019 0.0190.018 0.022 Victoria B/BJ/97 0.016 0.005 0.218 0.182 0.195 0.152 0.134lineage B/HK/01 0.038 0.021 0.142 0.172 0.132 0.084 0.121 B/MY/04 0.0580.023 0.079 0.094 0.076 0.076 0.074 B/BNE/08 0.010 0.006 0.238 0.1000.080 0.151 0.098 Yammagata B/AA/94 1.251 0.891 0.027 0.033 0.023 0.0230.023 lineage B/YSI/98 0.133 0.012 0.039 0.014 0.009 0.010 0.007B/JHB/99 0.021 0.012 0.304 nd nd nd nd B/SC/99 nd* nd 0.034 0.026 0.0220.023 0.023 B/FL/06 0.013 0.016 0.046 0.016 0.017 0.023 0.014 *nd = notdetermined

Table 9 shows the average IC₅₀ from two independent experiments. Theanti-HA antibodies neutralized all the influenza B viruses tested.FBD-56 and FBD-94 were more potent than the FBC-39, but showed somereduced activity against the B/AA/94 strain. The FBC-39 variants, LSL,FSL, LTL, and FTL neutralized all viruses to a similar or lower IC₅₀than FBC-39.

Example 4 Binding and Neutralization of Influenza A H9 Virus Strains

HA binding ELISAs were performed with similar methodology as in Example2, with the exception that the 384-well plates were coated for 2 hoursat room temperature with 3 μg/ml of recombinant HA derived frominfluenza A subtype H9 (A/chicken/HK/G9/97(H9N2)) in PBS. The resultsshowed that the FBC-39, and germlined variants LTL bound H9 HA withsimilar EC₅₀ values of 6.2 and 6.3 μg/ml respectively, and FBC-39 LSLand FTL bound with higher EC₅₀ of 41.7 and 46.1 μg/ml respectively(Table 10). In contrast the FBC-39 FSL bound only weakly at the highestdose tested 50 μg/ml, and no binding was seen with FBD-56 and FBD-94.

TABLE 10 Activity against influenza A/chicken/HK/G9/97(H9N2) BindingEC₅₀ Neutralization (μg/ml) IC₅₀ (μg/ml) FBD-56 nb* >50 FBD-94 nb >50FBC-39 6.2 0.17 FBC-39 LSL 41.7 0.59 FBC-39 FSL weak 1.70 FBC-39 LTL 6.30.09 FBC-39 FTL 46.1 0.43 Ctl mAb nb >50 *nb = no binding

To confirm the binding of the influenza A H9 HA protein was functionallyrelevant, a microneutralization assay was performed using similarmethodology as described in Example 3. For this assay, cold-adapted (ca)live attenuated influenza vaccine virus was generated by reversegenetics, containing the viral HA and NA genes from the A/chicken/HongKong/G9/97 (H9N2) virus in the context of the six internal protein genesof the ca A/Ann Arbor/6/60 (H2N2) virus with similar methodology asdescribed by Jin et al. (2003) Virology. 306:18-24). Results of themicroneutralization assay are shown in Table 10. Consistent with bindingprofile, FBC-39 and the variants potentially neutralized the H9N2 viruswith biologically relevant IC₅₀ values. FBC-39 and FBC-39 LTL had themost potent activity with IC₅₀ values of 0.17 and 0.09 μg/ml,respectively. As expected, the FBD-56, FBD-94, and the controlantibodies showed no neutralization activity at the highestconcentration tested (50 μg/ml).

Example 5 Epitope Identification by Selection of Monoclonal AntibodyResistant Mutants (MARMs)

Yamagata lineage influenza B virus (B/Florida/4/2006; B/FLA/06) andVictoria lineage influenza B virus (B/Malyasia/2506/2004; B/MY/04) wereincubated with high concentrations of FBC-39, FBD-56, and FBD-94(125×IC₅₀) for 1 hour before the mixture of virus and antibody wasadsorbed to MDCK cells at 30,000 TCID50 per well in 10×96-well platesand cultured in the presence of FBC-39, FBD-56, and FBD-94 (10×IC₅₀).Putative MARMs exhibiting the cytopathic effect (CPE) on the infectedcells up to 3 days after infection were isolated. The HA gene wereamplified by RT-PCR and subsequently sequenced, and then the isolatedvirus was confirmed for resistance by microneutralization assay. NoMARMS were isolated from B/FLA/09 virus when cultured in the presence ofFBC-39, FBD-56, or FBD-94. When the Victoria lineage (B/MY/04) virus wasused, MARMS were isolated in the presence of FBD-56 and FBD-94, but notin the presence of FBC-39. Sequence analysis revealed that two FBD-56MARMs contained single amino acid substitution at position 128 fromglutamic acid (E) to lysine (K) or valine (V) (Table 11). The FBD-94MARM harboured a single amino acid substitution at position 128 from Eto K (Table 11). A variant of the Yamagata lineage B/Florida/4/2006containing a single amino acid substitution at position 141 from glycine(G) to E (B/FLA/06 G141E) conferred an 8-fold reduction in FBC-39neutralization compared to the wildtype virus (B/FLA/06). Using thisB/FLA/09 G141E variant and Yamagata lineage virus B/Jiangsu/10/2003(B/JIN/03), a naturally circulating virus that contains an R at position141 (G141R), MARM isolation was repeated with only the FBC-39 mAb. OneMARM virus was isolated using the B/FLA/09 G141E virus with a singleamino acid change from G to arginine (R) at position 235 (Table 11). TwoB/JIN/03 escape mutant viruses were identified with single amino acidsubstitutions from serine (S) to isoleucine (I) at position 150, or fromE to leucine (L) at position 235 (Table 11), respectively. The aminoacid substitution identified in these influenza B MARMs are located inthe head region of HA (Wang et al. (2008) J. Virol. 82(6):3011-20),suggesting that FBC-39, FBD-56, and FBD-94 recognize epitopes on the HAhead of the influenza B virus, with FBD-56 and FBD-94 having a keycontact at position 128 and sharing a overlapping epitope, and FBC-39having a conformational epitope with important contact residues atpositions 141, 150, and 235.

TABLE 11 Amino Acid Substitutions Identified Through MARM SelectionB/FLA/06 B/FLA/06 B/MY/04 G141E B/JIN/03 FBC-39 *NF NF G235R S150I orE235L FBD-56 NF E128K {circumflex over ( )}NA NA or E128V FBD-94 NFE128K NA NA *NF = No MARM Found {circumflex over ( )}NA = Not Assayed

Example 6 Influenza B Anti-HA Antibodies Exhibit Fc-Effector Function

Antibodies have the potential to clear virus infected cells throughFc-effector function such as antibody dependent cellular cytotoxicity(ADCC), antibody dependent cellular phagocytosis, and complementdependent killing. To confirm the anti-HA antibodies exhibited ADCCactivity; we tested their ability to activate NK cells in the presenceof influenza B virus with an ADCC bioassay. This assay uses a human NKcell line (NK92) that has been stably transfected with the human FcgIIIAhigh affinity receptor and a luciferase transgene under the control ofthe NFAT promoter, in order to measure Fc effector activation. 96-wellplates were coated with 5.0×10⁴ TCID50/well of B/Hong Kong/330/2001(Victoria) virus stock. A serial dilution of FBD-94, FBC-39 as well asFc-effector null variants that contain two substitutions in the Fcregion, L234A and L235A (FBD-94 LALA and FBC-39 LALA) (Hezareh et al.(2001) J. Virol. 75(24):12161) were applied to the virus, and then NKcells were added at 5.0×10⁴ cells/well and incubated at 37° C. for 4hours. Luciferase was detected by the addition of Steady-Glo Reagent(Promega) and measured by envision plate reader. FIG. 1 shows that bothFBD-94 and FBC-39 exhibit a dose dependent influenza B ADCC activity,whereas the LALA variants showed no activity at the same concentrations.

Example 7 In Vivo Prophylactic and Therapeutic Effect of Anti-InfluenzaB IgGs in an Leathal Murine Model of Influenza Infection

The protective efficacy of influenza B neutralizing monoclonalantibodies was evaluated in a lethal influenza B murine model.

Prophylactic activity (FIG. 2A-D): To test prophylactic efficacy,six-to-eight week old BALB/c (Harlan Laboratories) mice wereadministered a single intraperitoneal (IP) injection of either FBC-39 orFBD-94 antibody at doses of 3, 1, 0.3, or 0.1 mg/kg in 100 μl volumes ingroups of eight. For each study, a group of control animals were treatedIP with a human isotype non-relevant control IgG at 3 mg/kg in 100 μlvolumes. Four hours after dosing, mice were inoculated intranasally with15 times the fifty percent mouse lethal dose (15 MLD₅₀) ofB/Sichuan/379/99 (Yamagata) (B/Sic/99) or 10 MLD₅₀ of the B/HongKong/330/2001 (Victoria) (B/HK/01) in a 50 μl volume. Mice were weighedon the day of virus challenge and monitored daily for weight loss andsurvival for 14 days (mice with body weight loss 25% were euthanized).Both FBC-39 and FBD-94 mAbs conferred protection in a dose-dependentmanner. FBC-39 and FBD-94 at 0.3 mg/kg or greater provided 90%-100%protection to the animals challenged with B/Sic/99 (FIGS. 2A and B) andB/HK/01 (FIGS. 2C and D). FBC-39 and FBD94 at lower dose of 0.1 mg/kgwere also highly protective against B/HK/01 with 90% and 80% survivalrate, respectively. As expected, none of the mice that received theisotype control mAb at 3 or 30 mg/kg survived the challenge of B/Sic/99or B/HK/01, respectively.

Therapeutic activity (FIG. 3A-D and FIGS. 4A and B): To assess thetherapeutic efficacy of the antibodies, mice were inoculated with 10MLD₅₀ of B/Sic/99 (Yamagata) or 5 MLD₅₀ of B/HK/01 (Victoria) andinjected with 10, 3, 1, or 0.3 mg/kg of FBC-39 or FBD-94 two days postinfection (pi). FBC-39 and FBD-94 provided complete protection toanimals challenged with B/Sic/99 when administered at 1 mg/kg or greater(FIGS. 3A and B). For the B/HK/01 infection, FBC-39 and FBD-94 at dosesof 0.3 mg/kg and greater provided complete protection (FIGS. 3C and D).As expected, the isotype control mAb given at 10 or 30 mg/kg failed toprotect mice with a survival rate of 10% or 20% for B/Sic/99 and B/HK/01infections, respectively.

To test the ability of the Flu B antibodies to protect over time, micewere inoculated with 5 MLD₅₀ of B/HK/01 and IP injected with 3 mg/kg ofFBC-39 or FBD-94 initiated at 1, 2, 3, or 4 days pi. FBC-39 protected100% of mice when administered on day 1 pi, and 80% and 70% on day 2 and3 pi respectively (FIG. 4A). FBD-94 protected 100% of mice whenadministered on day 1 and day 2 pi, and 80% and 60% on day 3 and day 4pi, respectively (FIG. 4B). As expected, mice treated with same dose ofnon-relevant isotype control antibody failed to protect mice with asurvival rate of 10%.

Example 8 Hemaglutination Inhibition Activity

To determine a possible mechanism of action for the influenza B antibodyfunctionality of the antibodies of the invention, hemagglutinationinhibition (HAI) assays were performed using a diverse group ofinfluenza B virus strains. The HAI assay detects antibodies that blockthe viral receptor engagement of the cellular surface expressed sialicacid by measuring the inhibition of virus-mediated agglutination oferythrocytes. Influenza B viruses (abbreviations as described belowTable 12) were adjusted to 4 HA units determined by incubation with0.05% turkey red blood cells (Lampire Biological Laboratories) in theabsence of antibody. In a 96-well U-bottom plate FBD-94 and FBC-39 IgGwas serially diluted in two-fold increments and diluted virus was addedto the wells. After 30 to 60 min incubation, 50 ul of 0.05% turkey redblood cells was added. Plates were incubated an additional 30 to 60minutes and observed for agglutination. The HAI titer was determined tobe the minimum effective concentration (nM) of antibody that completelyinhibited agglutination. Table 12 shows that FBD-94 and FBC39 had HAIactivity against all influenza B strains tested, providing evidence ofbinding to the globular head of the influenza B HA. Other antibodies ofthe invention show similar activity using HAI assays.

TABLE 12 Hemagglutination Inhibition Titer (nM) Viral Strain FBD-94FBC-39 B/Lee/40 (un) 1 5 B/AA/66 (un) 10 6 B/HK/72(Un) 3 8 B/BJ/97 (Vic)10 14 B/HK/01(Vic) 10 16 B/Mal/04 (Vic) 10 20 B/OH/05 (Vic) 10 24B/Bne/08 (Vic) 4 20 B/Yam/88 (Yam) 250 11 B/AA/94 (Yam) 5 6 B/Geo/98(Yam) 8 16 B/Ysh/98 (Yam) 10 13 B/Joh/99 (Yam) 10 18 B/Sic/99 (Yam) 5 10B/Vic/2000 (Yam) 8 16 B/Shg/02 (Yam) 0 16 B/Fla/4/06 (Yam) 5 7 B/Lee/40(B/Lee/40); B/AA/66 (ca B/Ann Arbor/1/66); B/HK/72 (B/Hong Kong/5/72);B/BJ/97 (ca B/Beijing/243/97 (victoria)), B/HK/01 (B/Hong Kong/330/2001(victoria)); B/Mal/04 (B/Malaysia/2506/2004 (victoria)); B/OH/05(B/Ohio/1/2005 (victoria)); B/BNE/08 (ca B/Brisbane/60/2008 (victoria));B/Yam/88 (B/Yamagata/16/88 (yamagata)); B/AA/94 (ca B/Ann Arbor/2/94(yamagata)); B/geo/98 (ca B/Georgia/02/98 (yamagata)); B/Ysh/98 (caB/Yamanashi/166/98 (yamagata)); B/Joh/99 (ca B/Johannesburg/5/99(yamagata)); B/Sic/99 (B/Sichuan/379/99 (yamagata)); B/Vic/00 (caBNictoria/504/2000 (yamagata)); B/Shg/02 (B/Shanghai/361/02 (yamagata));and B/FL/06 (B/Florida/4/06 (yamagata)).

All publications, patents and patent applications mentioned in thisspecification are herein incorporated by reference into thespecification to the same extent as if each individual publication,patent or patent application was specifically and individually indicatedto be incorporated herein by reference.

Sequence Information SEQ ID NO: 1 (FBD-56 VH DNA)GAAGTGCAGCTGGTGGAGTCTGGGGGACACTTGGTGCAGCCTGGCAGGTCCCTGAGACTCTCCTGTGCAGCCTCTGGATTCACCTTTGAGGATTATGCCATGAATTGGGTCCGGCAAGCTCCAGGGAAGGGCCTGGAGTGGGTCTCAGTCATTAGTTGGGACAGTGGTAGGATAGGCTATGCGGACTCTGTGAAGGGCCGATTCACCATCTCCAGAGACAACGCCAAGAACTCCTCGTATCTGCAAATGAACAGTCTGAGACCTGAGGACACTGCCTTGTATTATTGTGTAAGAGATATGTTGGCTTATTATTCTGACAATAGTGGCAAAAAATACAACGTCTACGGTATGGACGTCTGGGGCCAAGGGACCACGGTCACCGTCTCCTCAGSEQ ID NO: 2 (FBD-56 VH protein)EVQLVESGGHLVQPGRSLRLSCAASGFTFEDYAMNWVRQAPGKGLEWVSVISWDSGRIGYADSVKGRFTISRDNAKNSSYLQMNSLRPEDTALYYCVRDMLAYYSDNSGKKYNVYGMDVWGQGTTVTVSS SEQ ID NO: 3 (FBD-56 HCDR-1-Kabat): DYAMNSEQ ID NO: 4 (FBD-56 HCDR-2-Kabat): VISWDSGRIGYADSVKGSEQ ID NO: 5 (FBD-56 HCDR-3-Kabat): DMLAYYSDNSGKKYNVYGMDVSEQ ID NO: 6 (FBD-56 VL DNA)GAAATTGTGTTGACACAGTCTCCAGCCACCCTGTCTTTGTCTCCAGGGGAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTGTTTCCACCTTCTTAGCCTGGTACCAACAGAAACCTGGCCAGGCTCCCAGGCTCCTCATGTATGATGCATCCAACAGGGCCACTGGCATCCCAGCCAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGCCTAGAACCTGAAGATTTTGCAATTTACTACTGTCAGCAGCGTAGCCACTGGCCTCCTATCTTCGGCCAAGGGACACGACTGGAGATTAAAC SEQ ID NO: 7 (FBD-56 VL protein)EIVLTQSPATLSLSPGERATLSCRASQSVSTFLAWYQQKPGQAPRLLMYDASNRATGIPARFSGSGSGTDFTLTISSLEPEDFAIYYCQQRSHWPPIFGQGTR LEIKSEQ ID NO: 8 (FBD-56 LCDR-1-Kabat): ASQSVSTFLASEQ ID NO: 9 (FBD-56 LCDR-2-Kabat): DASNRATSEQ ID NO: 10 (FBD-56 LCDR-3-Kabat): QQRSHWPPISEQ ID NO: 11 (FBD-94 VH DNA)GAAGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTGCAACCTGGCAGGTCCCTGAGACTCTCCTGTGCAGTTTCTGGATTCATCTTTGAAGATTATGCCATAAACTGGGTCCGGCAAGCTCCAGGGAAGGGCCTGGAGTGGGTCTCAATTATTAGTTGGGACAGTGGTAGGATAGGCTACGCGGACTCTGTGAGGGGCCGATTCACCATCTCCAGAGACAACGCCAAGAACTCCTCGTTTCTGCAAATGAACAGTCTGAGACCCGAAGACACGGCCGTGTATTATTGTGTAAAAGATATGTTGGCGTATTATTATGATGGTAGCGGCATCAGGTACAACCTCTACGGTATGGACGTCTGGGGCCAAGGGACCACGGTCACCGTCTCCTCAGSEQ ID NO: 12 (FBD-94 VH protein)EVQLVESGGGLVQPGRSLRLSCAVSGFIFEDYAINWVRQAPGKGLEWVSIISWDSGRIGYADSVRGRFTISRDNAKNSSFLQMNSLRPEDTAVYYCVKDMLAYYYDGSGIRYNLYGMDVWGQGTTVTVSS SEQ ID NO: 13 (FBD-94 HCDR-1-Kabat): DYAINSEQ ID NO: 14 (FBD-94 HCDR-2-Kabat): IISWDSGRIGYADSVRGSEQ ID NO: 15 (FBD-94 HCDR-3-Kabat): DMLAYYYDGSGIRYNLYGMDVSEQ ID NO: 16 (FBD-94 VL DNA)GAAATTGTGTTGACACAGTCTCCAGCCACTCTGTCTTTGTCTCCAGGGGAAAGAGCCACCCTCTCCTGCAGGGCCAGTCGGAGTATTACCACCTTCTTAGCCTGGTACCAACAAAAACCTGGCCAGGCTCCCAGGCTCCTCATCTACGATGCATCCAACAGGGCCACTGGCGTCCCAGCCAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAACAGCCTAGAGCCTGACGATTTTGCAATTTATTACTGTCAGCAGCGTGACCACTGGCCTCCGATCTTCGGCCAAGGGACACGACTGGAGATTAAAC SEQ ID NO: 17 (FBD-94 VL protein)EIVLTQSPATLSLSPGERATLSCRASRSITTFLAVVYQQKPGQAPRLLIYDASNRATGVPARFSGSGSGTDFTLTINSLEPDDFAIYYCQQRDHWPPIFGQGTRLE IKSEQ ID NO: 18 (FBD-94 LCDR-1-Kabat): RASRSITTFLASEQ ID NO: 19 (FBD-94 LCDR-2-Kabat): DASNRATSEQ ID NO: 20 (FBD-94 LCDR-3-Kabat): QQRDHWPPISEQ ID NO: 21 (FBC-39 VH DNA)GAGGTGCAGCTGGTGGTGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGACTCAGTTTCCTTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGGCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCAGCATCTCAAGAGACGATTCAAAGAACATGCTGTTTCTGCATATGAGCAGCCTGAGAACCGAGGACACAGCCGTCTATTACTGCGCCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGG TCACCGTCTCCTCAGSEQ ID NO: 22 (FBC-39 VH protein)EVQLVVSGGGLVKPGGSLRLSCAASGLSFLNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFSISRDDSKNMLFLHMSSLRTEDTAVYYCATDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO: 23 (FBC-39 HCDR-1-Kabat): NAWMSSEQ ID NO: 24 (FBC-39 HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO: 25 (FBC-39 HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 26 (FBC-39 VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTTTTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO: 27 (FBC-39 VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYFCQQANSFPPTFGQGTK LEIKSEQ ID NO: 28 (FBC-39 LCDR-1-Kabat): RASQDISTWLASEQ ID NO: 29 (FBC-39 LCDR-2-Kabat): AASSLQSSEQ ID NO: 30 (FBC-39 LCDR-3-Kabat): QQANSFPPTSEQ ID NO:  31 (FBC-39 LSL VH DNA)GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGACTCTCTTTCCTTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO: 32 (FBC-39 LSL VH protein)EVQLVESGGGLVKPGGSLRLSCAASGLSFLNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO: 33 (FBC-39 LSL HCDR-1-Kabat): NAWMSSEQ ID NO: 34 (FBC-39 LSL HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO: 35 (FBC-39 LSL HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 36 (FBC-39 LSL VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO: 37 (FBC-39 LSL VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO: 38 (FBC-39 LSL LCDR-1-Kabat): RASQDISTWLASEQ ID NO: 39 (FBC-39 LSL LCDR-2-Kabat): AASSLQSSEQ ID NO: 40 (FBC-39 LSL LCDR-3-Kabat): QQANSFPPTSEQ ID NO: 41 (FBC-39 FSL VH DNA)GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGATTCTCTTTCCTTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO: 42 (FBC-39 FSL VH protein)EVQLVESGGGLVKPGGSLRLSCAASGFSFLNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO: 43 (FBC-39 FSL HCDR-1-Kabat): NAWMSSEQ ID NO: 44 (FBC-39 FSL HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO: 45 (FBC-39 FSL HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 46 (FBC-39 FSL VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO: 47 (FBC-39 FSL VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO: 48 (FBC-39 FSL LCDR-1-Kabat): RASQDISTWLASEQ ID NO: 49 (FBC-39 FSL LCDR-2-Kabat): AASSLQSSEQ ID NO: 50 (FBC-39 FSL LCDR-3-Kabat): QQANSFPPTSEQ ID NO: 51 (FBC-39 LTL VH DNA)GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGACTCACTTTCCTTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO: 52 (FBC-39 LTL VH protein)EVQLVESGGGLVKPGGSLRLSCAASGLTFLNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO: 53 (FBC-39 LTL HCDR-1-Kabat): NAWMSSEQ ID NO: 54 (FBC-39 LTL HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO: 55 (FBC-39 LTL HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 56 (FBC-39 LTL VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO: 57 (FBC-39 LTL VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO: 58 (FBC-39 LTL LCDR-1-Kabat): RASQDISTWLASEQ ID NO: 59 (FBC-39 LTL LCDR-2-Kabat): AASSLQSSEQ ID NO: 60 (FBC-39 LTL LCDR-3-Kabat): QQANSFPPTSEQ ID NO: 61 (FBC-39 FTL VH DNA)GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGATTCACTTTCCTTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO: 62 (FBC-39 FTL VH protein)EVQLVESGGGLVKPGGSLRLSCAASGFTFLNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO: 63 (FBC-39 FTL HCDR-1-Kabat): NAWMSSEQ ID NO: 64 (FBC-39 FTL HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO: 65 (FBC-39 FTL HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 66 (FBC-39 FTL VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO: 67 (FBC-39 FTL VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO: 68 (FBC-39 FTL LCDR-1-Kabat): RASQDISTWLASEQ ID NO: 69 (FBC-39 FTL LCDR-2-Kabat): AASSLQSSEQ ID NO: 70 (FBC-39 FTL LCDR-3-Kabat): QQANSFPPTSEQ ID NO: 71 (FBC-39 VH protein-with variable amino acids) (See FIG. 6)SEQ ID NO: 72 (FBC-39 VL protein-with variable amino acids) (See FIG. 7)SEQ ID NO:  73 (FBC-39 FSS VH DNA)GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGATTCTCTTTCAGTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO:  74 (FBC-39 FSS VH protein)EVQLVESGGGLVKPGGSLRLSCAASGFSFSNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO:  75 (FBC-39 FSS HCDR-1-Kabat): RASQDISTWLASEQ ID NO:  76 (FBC-39 FSS HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO:  77 (FBC-39 FSS HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO:  78 (FBC-39 FSS HCDR-1-IMGT): GFSFSNAWSEQ ID NO:  79 (FBC-39 FSS HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO:  80 (FBC-39 FSS HCDR-3-IMGT): TTDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO:  81 (FBC-39 FSS VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO:  82 (FBC-39 FSS VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO:  83 (FBC-39 FSS LCDR-1-Kabat): RASQDISTWLASEQ ID NO:  84 (FBC-39 FSS LCDR-2-Kabat): AASSLQSSEQ ID NO:  85 (FBC-39 FSS LCDR-3-Kabat): QQANSFPPTSEQ ID NO:  86 (FBC-39 FSS LCDR-1-IMGT): QDISTWSEQ ID NO:  87 (FBC-39 FSS LCDR-2-IMGT): AASSEQ ID NO:  88 (FBC-39 FSS LCDR-3-IMGT): QQANSFPPTSEQ ID NO:  89 (FBC-39 LTS VH DNA):GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGACTCACTTTCAGTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO:  90 (FBC-39 LTS VH protein):EVQLVESGGGLVKPGGSLRLSCAASGLTFSNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO:  91 (FBC-39 LTS HCDR-1-Kabat): RASQDISTWLASEQ ID NO:  92 (FBC-39 LTS HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO:  93 (FBC-39 LTS HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO:  94 (FBC-39 LTS HCDR-1-IMGT): GLTFSNAWSEQ ID NO:  95 (FBC-39 LTS HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO:  96 (FBC-39 LTS HCDR-3-IMGT): TTDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO:  97 (FBC-39 LTS VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO:  98 (FBC-39 LTS VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO:  99 (FBC-39 LTS LCDR-1-Kabat): RASQDISTWLASEQ ID NO:  100 (FBC-39 LTS LCDR-2-Kabat): AASSLQSSEQ ID NO:  101 (FBC-39 LTS LCDR-3-Kabat): QQANSFPPTSEQ ID NO:  102 (FBC-39 LTS LCDR-1-IMGT): QDISTWSEQ ID NO:  103 (FBC-39 LTS LCDR-2-IMGT): AASSEQ ID NO:  104 (FBC-39 LTS LCDR-3-IMGT): QQANSFPPTSEQ ID NO:  105 (FBC-39 FTS VH DNA):GAGGTGCAGCTGGTGGAGTCTGGGGGAGGCTTGGTAAAGCCTGGGGGGTCCCTTAGACTCTCCTGTGCAGCCTCTGGATTCACTTTCAGTAACGCCTGGATGAGCTGGGTCCGCCAGGCTCCAGGGAAGGGCCTGGAGTGGGTTGGCCGTATTAAAAGTAATACTGATGGTGGGACAACAGACTACGCCGCACCCGTGAAAGGCAGATTCACCATCTCAAGAGACGATTCAAAGAACACGCTGTATCTGCAAATGAGCAGCCTGAAAACCGAGGACACAGCCGTCTATTACTGCACCACAGATGGACCTTACTCTGACGATTTTAGAAGTGGTTATGCCGCACGCTACCGTTATTTCGGAATGGACGTCTGGGGCCAAGGGACCACGGT CACCGTCTCCTCASEQ ID NO:  106 (FBC-39 FTS VH protein):EVQLVESGGGLVKPGGSLRLSCAASGFTFSNAWMSWVRQAPGKGLEWVGRIKSNTDGGTTDYAAPVKGRFTISRDDSKNTLYLQMSSLKTEDTAVYYCTTDGPYSDDFRSGYAARYRYFGMDVWGQGTTVTVSSSEQ ID NO:  107 (FBC-39 FTS HCDR-1-Kabat): RASQDISTWLASEQ ID NO:  108 (FBC-39 FTS HCDR-2-Kabat): RIKSNTDGGTTDYAAPVKGSEQ ID NO:  109 (FBC-39 FTS HCDR-3-Kabat): DGPYSDDFRSGYAARYRYFGMDVSEQ ID NO:  110 (FBC-39 FTS HCDR-1-IMGT): GFTFSNAWSEQ ID NO:  111 (FBC-39 FTS HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO:  112 (FBC-39 FTS HCDR-3-IMGT): TDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO:  113 (FBC-39 FTS VL DNA)GACATCCAGATGACCCAGTCTCCATCTTCCGTGTCTGCATCTGTGGGAGACAGAGTCACCATCACTTGTCGGGCGAGTCAGGATATTAGCACCTGGTTAGCCTGGTATCAGCAGAAACCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCATCAAGATTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGCCTGCAGCCTGAAGATTTTGCAACTTACTATTGTCAGCAGGCTAACAGTTTCCCTCCGACTTTTGGCCAGGGGACCAAGCTGGAGATCAAAC SEQ ID NO:  114 (FBC-39 FTS VL protein)DIQMTQSPSSVSASVGDRVTITCRASQDISTWLAWYQQKPGKAPKLLIYAASSLQSGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQANSFPPTFGQGTK LEIKSEQ ID NO:  115 (FBC-39 FTS LCDR-1-Kabat): RASQDISTWLASEQ ID NO:  116 (FBC-39 FTS LCDR-2-Kabat): AASSLQSSEQ ID NO:  117 (FBC-39 FTS LCDR-3-Kabat): QQANSFPPTSEQ ID NO:  118 (FBC-39 FTS LCDR-1-IMGT) QDISTWSEQ ID NO:  119 (FBC-39 FTS LCDR-2-IMGT): AASSEQ ID NO:  120 (FBC-39 FTS LCDR-3-IMGT): QQANSFPPTSEQ ID NO: 121 (FBC-39 HCDR-1-IMGT): GLSFLNAWSEQ ID NO: 122 (FBC-39 HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO: 123 (FBC-39 HCDR-3-IMGT): TDGPYSDDFRSGYAARYRYFGMDVWSEQ ID NO: 124 (FBC-39 LCDR-1-IMGT): QDISTWSEQ ID NO: 125 (FBC-39 LCDR-2-IMGT): AASSEQ ID NO: 126 (FBC-39 LCDR-3-IMGT): QQANSFPPTSEQ ID NO: 127 (FBC-39 LSL HCDR-1-IMGT): GLSFLNAWSEQ ID NO: 128 (FBC-39 LSL HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO: 129 (FBC-39 LSL HCDR-3-IMGT): TTDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 130 (FBC-39 LSL LCDR-1-IMGT): QDISTWSEQ ID NO: 131 (FBC-39 LSL LCDR-2-IMGT): AASSEQ ID NO: 132 (FBC-39 LSL LCDR-3-IMGT): QQANSFPPTSEQ ID NO: 133 (FBC-39 FSL HCDR-1-IMGT): GFSFLNAWSEQ ID NO: 134 (FBC-39 FSL HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO: 135 (FBC-39 LSL HCDR-3-IMGT): TTDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 136 (FBC-39 FSL LCDR-1-IMGT): QDISTWSEQ ID NO: 137 (FBC-39 FSL LCDR-2-IMGT): AASSEQ ID NO: 138 (FBC-39 FSL LCDR-3-IMGT): QQANSFPPTSEQ ID NO: 139 (FBC-39 LTL HCDR-1-IMGT): GLTFLNAWSEQ ID NO: 140 (FBC-39 LTL HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO: 141 (FBC-39 LTL HCDR-3-IMGT): TTDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 142 (FBC-39 LTL LCDR-1-IMGT): QDISTWSEQ ID NO: 143 (FBC-39 LTL LCDR-2-IMGT): AASSEQ ID NO: 144 (FBC-39 LTL LCDR-3-IMGT): QQANSFPPTSEQ ID NO: 145 (FBC-39 FTL HCDR-1-IMGT): GFTFLNAWSEQ ID NO: 146 (FBC-39 FTL HCDR-2-IMGT): IKSNTDGGTTSEQ ID NO: 147 (FBC-39 FTL HCDR-3-IMGT): TTDGPYSDDFRSGYAARYRYFGMDVSEQ ID NO: 148 (FBC-39 FTL LCDR-1-IMGT): QDISTWSEQ ID NO: 149 (FBC-39 FTL LCDR-2-IMGT): AASSEQ ID NO: 150 (FBC-39 FTL LCDR-3-IMGT): QQANSFPPT

1. An isolated antibody or antigen binding fragment thereof that iscapable of binding to influenza B virus hemagglutinin (HA) andneutralizing influenza B virus in two phylogenetically distinct lineagescomprising a VH of SEQ ID NO.: 62 and VL of SEQ ID NO.
 67. 2. Theisolated antibody or antigen binding fragment thereof according to claim1, wherein the antibody or antigen binding fragment thereof is capableof binding to Yamagata lineage influenza B virus selected from: B/AA/94(ca B/Ann Arbor/2/94 (yamagata)); BNSI/98 (ca BNamanashi/166/98(yamagata)); B/JHB/99 (ca B/Johannesburg/5/99 (yamagata)); B/SC/99(B/Sichuan/379/99 (yamagata)); B/FL/06 (B/Florida/4/2006 (yamagata));Victoria lineage influenza B virus selected from: B/BJ/97 (caB/Beijing/243/97 (victoria)), B/HK/01 (B/Hong Kong/330/2001 (victoria));B/MY/04 (B/Malaysia/2506/2004 (victoria)); B/BNE/08 (caB/Brisbane/60/2008 (victoria)); pre-divergent influenza B strainsselected from: B/Lee/40 (B/Lee/40); B/AA/66 (ca B/Ann Arbor/1/66);B/HK/72 (B/Hong Kong/5/72); and combinations thereof.
 3. The isolatedantibody or antigen binding fragment thereof according to claim 1,wherein the antibody or antigen binding fragment thereof is capable ofbinding to influenza B virus hemagglutinin (HA) and influenza A virushemagglutinin (HA) and neutralizing at least one Yamagata lineageinfluenza B virus or at least one Victoria lineage influenza B virus andat least one influenza A virus subtype.
 4. The isolated antibody orantigen binding fragment thereof according to claim 3, wherein theantibody is capable of binding to and neutralizing influenza A virussubtype 1 or subtype 2 hemagglutinin.
 5. The isolated antibody orantigen binding fragment thereof according to claim 3, wherein theantibody is capable of binding to and neutralizing influenza A virusgroup 1 subtype selected from: H8, H9, H11, H12, H13, H16 and variantsthereof.
 6. An isolated nucleic acid encoding an antibody or antigenbinding fragment thereof according to claim
 1. 7. A method formanufacturing an antibody or antigen binding fragment thereof,comprising culturing a host cell comprising a nucleic acid according toclaim 6 under conditions suitable for expression of the antibody orfragment thereof and isolating said antibody or antigen binding fragmentthereof.
 8. A composition comprising an antibody or antigen bindingfragment thereof according to claim 1 and 25 mM His and 0.15M NaCl at pH6.0
 9. A method for prophylaxis or treatment of influenza B infection ina subject comprising administering an effective amount of an antibody orantigen binding fragment thereof according to claim 1 to the subject.10. The use of an antibody or fragment thereof according to claim 1 forin vitro diagnosis of influenza B infection in a subject comprisingcontacting a sample from the subject with said antibody or fragmentthereof to detect the presence of influenza B.
 11. An isolated antibodyor antigen binding fragment thereof that is capable of binding toinfluenza B virus hemagglutinin (HA) and neutralizing influenza B virusin two phylogenetically distinct lineages, wherein the antibody orantigen binding fragment thereof includes a set of six CDRs: HCDR-1,HCDR-2, HCDR-3, LCDR-1, LCDR-2, LCDR-3, in which the set of six CDRs isHCDR-1 of SEQ ID NO.: 145, HCDR-2 of SEQ ID NO.: 146, HCDR-3 of SEQ IDNO.: 147, LCDR-1 of SEQ ID NO.: 148, LCDR-2 of SEQ ID NO.: 149 andLCDR-3 of SEQ ID NO.:
 150. 12. The isolated antibody or antigen bindingfragment thereof according to claim 11, wherein the antibody or antigenbinding fragment thereof is capable of binding to Yamagata lineageinfluenza B virus selected from: B/AA/94 (ca B/Ann Arbor/2/94(yamagata)); BNS1/98 (ca BNamanashi/166/98 (yamagata)); B/JHB/99 (caB/Johannesburg/5/99 (yamagata)); B/SC/99 (B/Sichuan/379/99 (yamagata));B/FL/06 (B/Florida/4/2006 (yamagata)); Victoria lineage influenza Bvirus selected from: B/BJ/97 (ca B/Beijing/243/97 (victoria)), B/HK/01(B/Hong Kong/330/2001 (victoria)); B/MY/04 (B/Malaysia/2506/2004(victoria)); B/BNE/08 (ca B/Brisbane/60/2008 (victoria)); pre-divergentinfluenza B strains selected from: B/Lee/40 (B/Lee/40); B/AA/66 (caB/Ann Arbor/1/66); B/HK/72 (B/Hong Kong/5/72); and combinations thereof.13. The isolated antibody or antigen binding fragment thereof accordingto claim 11, wherein the antibody or antigen binding fragment thereof iscapable of binding to influenza B virus hemagglutinin (HA) and influenzaA virus hemagglutinin (HA) and neutralizing at least one Yamagatalineage influenza B virus or at least one Victoria lineage influenza Bvirus and at least one influenza A virus subtype.
 14. The isolatedantibody or antigen binding fragment thereof according to claim 13,wherein the antibody is capable of binding to and neutralizing influenzaA virus subtype 1 or subtype 2 hemagglutinin.
 15. The isolated antibodyor antigen binding fragment thereof according to claim 13, wherein theantibody is capable of binding to and neutralizing influenza A virusgroup 1 subtype selected from: H8, H9, H11, H12, H13, H16 and variantsthereof.
 16. An isolated nucleic acid encoding an antibody or antigenbinding fragment thereof according to claim
 11. 17. A method formanufacturing an antibody or antigen binding fragment thereof,comprising culturing a host cell comprising a nucleic acid according toclaim 16 under conditions suitable for expression of the antibody orfragment thereof and isolating said antibody or antigen binding fragmentthereof.
 18. A composition comprising an antibody or antigen bindingfragment thereof according to claim 11 and 25 mM His and 0.15M NaCl atpH 6.0
 19. A method for prophylaxis or treatment of influenza Binfection in a subject comprising administering an effective amount ofan antibody or antigen binding fragment thereof according to claim 11 tothe subject.
 20. A method for prophylaxis or treatment of influenza Aand influenza B infection in a subject comprising administering aneffective amount of an antibody or antigen binding fragment thereofaccording to claim 11 to the subject.
 21. The use of an antibody orfragment thereof according to claim 11 for in vitro diagnosis ofinfluenza B infection in a subject comprising contacting a sample fromthe subject with said antibody or fragment thereof to detect thepresence of influenza B.